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Alessandro Giuseppe Antonio Anastasio Volta's father, Filippo, was a minor nobleman of Lombardy, a district in north Italy. He married Maddena dei Conti Inzaghi, who came from another established family of the region. Alessandro seemed dull-witted as a child, not speaking until the age of four. He developed rapidly into a model student, however, and continued classical studies until he was sixteen. He had the command of several languages by then, but he was most strongly attracted to the study of the natural sciences, especially physics, chemistry, and electricity. Volta began publishing scientific papers at the age of twenty-four. While fishing one day on a lake near his home, he noticed bubbles rising to the surface, especially in the shallows and marshes. He began collecting samples of the vapors rising above the bubbles and learned that they comprised a flammable gas. These marsh vapors are now known as methane gas, which is produced when organic material decays. Volta published his findings in what became a widely read scientific paper. Volta was almost fifty when he married Signorina Teresa Peregrini, the youngest daughter of a local nobleman. The couple had three sons: Zanino, Flaminio, and Luigi. Zanino was elected mayor of Como, while Flaminio and Luigi became publishers of a periodical devoted to applied science and industry. Volta's scientific productivity declined significantly, however, once he became a father. While examining the conclusions of Luigi Galvani, who had postulated the existence of "animal electricity," Volta found instead that the natural current seen in this experiment resulted from contact between two dissimilar metals. Volta also observed that current flowed when metal touched some fluids. He learned that the effect could be strengthened when dissimilar metals, such as zinc and silver, were interleaved with moist paper pads. INSET: Count Alessandro Volta.

Julian Seymour Schwinger was born in New York City in 1918. His father, a clothing designer, was a successful businessman, and Schwinger grew up in an upper-middle-class environment. A true child prodigy, Schwinger was graduated from Townsend Harris High School, one of the premier academic preparatory schools in the country, at the age of sixteen. Following his graduation, he enrolled at the City College of New York, but he transferred to Columbia University after a year upon the suggestion I. I. Rabi, a noted physicist at Columbia who recognized Schwinger's unusual aptitude in theoretical physics. As an undergraduate at City College, Schwinger had already written one research paper on quantum electrodynamics. He published several additional papers as an undergraduate and, in fact, completed his doctoral dissertation before receiving his bachelor of science degree in physics from Columbia in 1936. He continued at Columbia for a year, working with Rabi, before spending eighteen months at the University of Wisconsin. In 1939, following his return to New York, Schwinger was awarded a Ph.D. in physics from Columbia University. He spent the next two years at the University of California, Berkeley, working with J. Robert Oppenheimer and other theoreticians. During this time, his research focused on the electromagnetic properties of deuterium and many particle systems. In 1941, Schwinger accepted an offer of an instructor position at Purdue University. INSET: Julian Seymour Schwinger.

Frederick Sanger was born in Rendcombe, Gloucestershire, England, on August 13, 1918. The son of a physician, he spent his early education at Bryanston School. Sanger attended Cambridge University for his entire university education, earning first a bachelor of arts degree in 1939 and then a doctorate in 1943 through St. John's College at Cambridge. He continued his biochemistry research at Cambridge as a research fellow until 1951, at which time he joined the staff of the Medical Research Council. During the 1940's and 1950's, much chemical research focused on the hereditary molecule deoxyribonucleic acid (DNA) and proteins, the products of DNA. Sanger's primary research interest at this time was in determining the exact amino acid sequence of a protein. In the early 1940's, he experienced a significant breakthrough toward that end. In 1945, he devised a method to use the chemical 2,4-dinitrofluorobenzene, later known as Sanger's reagent, to label one end of the protein chain. Sanger could then use acid to break up the protein into smaller fragments. Other scientists had designed a method to separate the individual amino acids from a mixture called paper chromatography. Sanger planned to break down the sequence of amino acids partially; attach his reagent to one end, break these labeled fragments down to individual amino acids, and separate them using paper chromatography. In this way; he could identify which amino acid was labeled. By painstakingly repeating this procedure many times, he could generate overlapping fragments of the protein and then, as if working a jigsaw puzzle, deduce the order of the amino acids. The protein hormone insulin had been isolated some twenty-five years earlier and was known to consist of two connected chains of fifty amino acids. Sanger chose this protein, which he obtained from the pancreatic tissue of cattle, for his sequence experiment. INSET: Frederick Sanger.

Vera C. Rubin was born Vera Cooper in Philadelphia, Pennsylvania, on July 23, 1928. Her parents were Philip Cooper, an electrical engineer, and Rose Applebaum Cooper. In 1938, the family moved to Washington, D.C. Vera developed an interest in astronomy at an early age. She attended Vassar College in Poughkeepsie, New York, earning her bachelor's degree in 1948. She was encouraged by the example of Maria Mitchell, the first American woman to become a noted astronomer, who had been a professor at Vassar in the late nineteenth century. In 1948, Cooper married Robert Rubin, a graduate student in physical chemistry at Cornell University in Ithaca, New York. She attended Cornell with her husband, earning her master's degree in 1951. Vera Rubin presented her first paper, "Rotation of the Universe," to the American Astronomical Society in December, 1950. In it, she offered findings that supported the idea that galaxies in different regions of the universe were moving away from the earth at different speeds that could not be explained fully by the general expansion of the universe. Her paper was soundly rejected by most astronomers, but she was vindicated in 1956 when French astronomer Gérard de Vaucouleurs used her work to support his concept of the Local Supercluster, a vast conglomerate of many clusters of galaxies, including the Milky Way. INSET: Vera C. Rubin.

Isaac Newton was born prematurely on Christmas Day; 1642--according to the Julian calendar, or January 4, 1643, by the current Gregorian calendar--in Woolsthorpe, Lincolnshire, England, and was not expected to live. His father, the lord of the manor of a small estate, died before Isaac was born. Newton attended the village school but showed little to indicate his great intellect. When he was twelve, he began attending the King's School in nearby Grantham. After four years, his mother took him out in order to manage the farm, but two years of mediocre performance persuaded her to allow him to return to school and prepare for college. In 1661, Newton entered Trinity College at Cambridge University. Shortly after arriving at Cambridge, Newton came to the attention of the mathematician Isaac Barrow. Under Barrow's tutelage, Newton began to display his enormous genius. He would win a mathematical scholarship in 1664, and, when he was graduated in 1665, Barrow resigned his chair in favor of his pupil. The year 1665 saw the bubonic plague reach Cambridge. The school was closed and the population dispersed to help control the spread of the disease. Newton returned to Woolsthorpe and remained there until the end of March, 1666. This period gave him months of uninterrupted thought and allowed him to complete work on some of the most revolutionary scientific achievements in history. The advances that Newton made during this period include his discovery of the calculus, the law of gravity, his three laws of motion, several properties of optics, and the invention of the reflecting telescope. News of Newton's work in optics reached the preeminent Royal Society of London, and he was elected a member. He was also invited to present his findings in a paper. He presented not only the paper but also his reflecting telescope, which remains one of the most prized possessions of the society. INSET: Sir Isaac Newton.

Max Born was born on December 11, 1882, in Breslau, Germany. His father, Gustav, was a professor of anatomy at the University of Breslau. His mother, Margarethe, died when Born was four years old. In 1890, his father married Bertha Lipstein. Her love of music probably accounted for Born's becoming an accomplished pianist. Born entered the University of Breslau in 1901, spending his next two summers studying at Heidelberg and Zürich. He studied a wide range of subjects, but his greatest interest lay in the areas of mathematics and physics. In 1904, he entered the University of Göttingen, where he became David Hilbert's private assistant. He also studied special relativity under Hermann Minkowski. Felix Klein was so impressed with Born's seminar paper on the stability of elastic wires that he used it as the topic for a university competition. Born was more interested at the time in relativity and declined to enter a paper. Klein, who was very powerful at the university, obliged Born to submit a paper, which won the competition and became the dissertation that earned Born a Ph.D. in 1907. INSET: Max Born.

Karl Landsteiner's father, Leopold, was a prominent Viennese journalist who died when his son was only six years old. Thus, Karl was brought up by his widowed mother, Fanny Hess Landsteiner. After his graduation from the University of Vienna with a medical degree in 1891, Landsteiner received sound training in organic chemistry from Arthur Hantzsch at the University of Zurich, in Switzerland, as well as from Emil Fischer at the University of Würzburg, and E. Bamberger at the University of Munich, both in Germany. While employed as an assistant at the department of pathological anatomy at the University of Vienna, Landsteiner wrote a footnote in his only paper published in 1900 which dealt with natural antibodies. The footnote contained a significant observation: "The serum of healthy human beings not only agglutinates animal red cells, but also often those of human origin, from other individuals." Landsteiner used his own blood in the agglutination experiments and, in 1901, published a short, definitive paper entitled "'Doer Agglutinationscheinungen normalen menschlichen Blutes" (on the agglutination of normal human blood), describing his classic effort on the identification of three blood groups: A, B, and O. For almost two decades, from 1903 to 1922, Landsteiner shifted gears and focused his attention on microbiology. INSET: Karl Landsteiner.

Christiaan Huygens (pronounced "HOY-gehnz") was born in The Hague in 1629. His father was a very influential and important man who was friends with the philosopher René Descartes. Huygens did not have formal schooling in his early years, but instead studied at home. From the age of fifteen, he read the works of Descartes, which was to have a profound impact on his later views of science. At the age of sixteen, Huygens was sent to the University of Leiden to study law. In 1647, he transferred to the new University of Breda, which his father directed. Huygens never married, and he devoted his entire life to the advancement of mathematics and the sciences. In 1654, he published a paper on a new way to determine the area of circles accurately. In 1655, Huygens worked with his brother to develop a better way of grinding lenses. Together, they built his first telescope, with which he studied Saturn. That same year, Huygens discovered Saturn's largest moon, Titan. He also was able to see that Saturn's strange appearance was attributable to a disk around the planet in the same plane as Titan's orbit. Huygens published his discovery of Saturn's moon in 1656. For fear of ridicule, however, he did not wish to publish his finding of its rings without further study. In order to prove that he saw the rings first, in case someone else reported them in the meantime, he encoded the discovery in an anagram in his paper about Saturn's moon. In a stroke of genius, he realized that Saturn's rings could not be solid but were likely composed of individual particles. Huygens was also one of the first persons to measure the rotational period of the planet Mars by timing the passage of surface markings across the face of the planet. He also used a micrometer of his own invention to measure the angular sizes of the planets. INSET: Christiaan Huygens.

Subrahmanyan Chandrasekhar (pronounced "chan-drah-SEEK-hahr") was born on October 19, 1910, in Lahore, India, to Chandrasekhara Subrahmanyan Ayyar and Sitalakshmi Ayyar. Sir Chandrasekhara Venkata Raman, a Nobel Prize-winning physicist, was his uncle. Taught at home until he was eleven, Subrahmanyan Chandrasekhar was admitted in 1921 into the Hindu High School in Triplicane, considered the best school in Madras. He was regarded as a prodigy, having mastered permutations and combinations, conic sections, coordinate geometry, calculus, and differential equations far ahead of his class. At fifteen, he became a freshman at the Presidency College of the University of Madras. While studying for his B.A. honors degree, he was inspired by the example of Srinivasa Ramanujan, the mathematical genius who had died only a few years earlier. While Chandrasekhar was pursuing mathematical physics in college, his uncle's discovery in 1928 of the Raman effect, which received international acclaim, became a turning point in his life. Stimulated by a meeting with Arnold Sommerfeld in Madras in 1928, Chandrasekhar launched into a study of the new discoveries in atomic physics and statistical mechanics and in 1929 had his first paper published in the prestigious Proceedings of the Royal Society of London. Two other papers were ready to be published in the Philosophical Magazine, and several others were in progress. In 1930, he received his B.A. honors degree and was offered a scholarship to study abroad by the government of India. On his way to England that year, he made the discovery that revolutionized stellar physics. Working on the theory of the evolution of white dwarf stars (such as the sun) from a relativistic standpoint, Chandrasekhar found that there is an upper limit to the mass of a star that will evolve into a white dwarf. INSET: Subrahmanyan Chandrasekhar.

Otto Stern (in German, pronounced "shtehrn") was born in 1888, the first of five children who would be born to Oskar Stern and Eugenie Rosenthal. Oskar came from a prosperous Jewish family of grain merchants and flour millers. As a college student, the family prosperity allowed Otto to wander among the universities of Germany, pursuing whatever interested him. Stern attended lectures on theoretical physics by Arnold Sommerfeld, a premier physicist of the day. He was fascinated by Ludwig Boltzmann's works on molecular theory and statistical mechanics and by the works on thermodynamics of Rudolf J. E. Clausius and Walther Hermann Nernst. Eventually, Stern returned to the University of Breslau to pursue his interests in thermodynamics and to earn a doctorate in physical chemistry. From 1912 to 1919, Stem's scientific activity was as a theorist. For the first two years, he worked as a postdoctoral assistant to Albert Einstein, who became a lifelong friend. Although Einstein was a theorist, perhaps the most important lessons that Stern learned from Einstein were which questions to ask and what experiments to attempt in order to find the answers. Stern and Einstein coauthored a paper showing that molecular motion need not cease at a temperature of absolute zero. Stern also published a paper in which he calculated the absolute entropy (disorder) of a monatomic gas. INSET: Otto Stern.

Erwin Schrödinger (pronounced "SHROYdihng-ur"), an only child, was born to Rudolf Schrödinger and Georginer Bauer, a daughter of Rudolf's chemistry professor. Schrödinger's father, the owner of a successful oil cloth factory; was a highly gifted man with a broad education and broad interests that he pursued throughout his life. The young Erwin was first educated at home, taking lessons twice a week from a visiting elementary school teacher. He attributed his interest in scientific, literary, and philosophical matters to his father, however, whom he would later describe as "his friend, teacher, and tireless partner in conversation." At the age of eleven, Schrödinger entered the Academische Gymnasium and he studied mathematics and physics, as well as classical languages and German poetry. After his graduation in 1910, Schrödinger stayed on as an assistant at the university's Second Physics Institute until the outbreak of World War I, when he was mobilized into the Imperial Army. He spent the three years following the war studying and teaching in Vienna, Jena, Stuttgart, and Breslau. Shortly after his arrival in Breslau in 1921, he accepted an offer from the University of Zurich to assume the professorship formerly held by Albert Einstein and Max von Laue. Schrödinger remained in Zurich for six years, enjoying the friendship of his colleagues--among whom were the mathematician Hermann Weyl and the physicist Peter J. W. Debye--and pursuing a number of problems in theoretical physics. He wrote papers dealing with specific heats of solids, problems of thermodynamics from a statistical point of view, and atomic spectra. He also studied the theory of color vision and wrote a paper on color blindness. His great discovery; Schrödinger's wave equation, was made at the end of this period, during the winter of 1925-1926. INSET: Erwin Schrödinger.

Edwin Ray Lankester, the son of a respected microscopist who cofounded the Quarterly Journal of Microscopical Science, met many scientists as a child. As a schoolboy, he attended popular lectures given by Thomas Henry Huxley, who became his mentor, and, in 1861, he published his first paper, a letter to The Geologist on a fossil animal. In the mid-1860's, Lankester published several papers on earthworms, attracting the attention of Charles Darwin. After receiving a Radcliffe Traveling Fellowship, Lankester made microscopical studies of marine species in Naples, Italy, and learned German laboratory techniques and methods of teaching. In 1872, he earned his master's degree. At this time, science education was very weak at both Oxford and Cambridge Universities. Lankester became convinced that science education in England had to be reformed on the German model. At Oxford, he petitioned to teach in the museum but was refused. At University College, London, however, he taught in the zoological laboratory in the museum, where he emphasized practical laboratory work. His equipment included aquariums for saltwater and freshwater species. Lankester's efforts at University College turned it into a major center for teaching and research into evolutionary relationships. His studies in Naples instilled in Lankester the desire to establish a laboratory to study marine species in England. Lankester's public addresses played an important role in generating popular and official interest, leading to the founding of the Marine Biological Association in 1884. In 1888, its laboratory at Plymouth opened and was the only English facility able to participate in an international study of the North Sea from 1899 to 1901.In 1882, Lankester discovered a blood parasite in frogs that scientists later recognized as a relative of the parasite that causes malaria. He also rediscovered in frogs a parasite related to those causing sleeping sicknesses. INSET: Sir Edwin Ray Lankester.

Niels Kaj Jerne (pronounced "YEHR-neh") was born on December 23, 1911, in London, England. Shortly after his birth, his family moved to Denmark and later to the Netherlands, where Jerne earned his bachelor's degree at the age of sixteen. He studied physics for two years at the University of Leiden and, twelve years later, entered the University of Copenhagen to study medicine. While working for his doctorate, Jerne also held a research position at the Danish State Serum Institute. His doctoral research dealt with the strength of interaction between antigens (foreign substances such as viruses, bacteria, and toxins) and antibodies (chemicals produced by immune cells to defend against antigens). He showed that antibody binding strength increases with every exposure to antigen. As a research fellow at the California Institute of Technology (Caltech), Jerne published a landmark paper entitled "The Natural Selection Theory of Antibody Formation," in which he proposed a revolutionary theory explaining an animal's ability to produce antibodies against a virtually limitless array of antigens. This paper provided the basis for the now universally accepted clonal selection theory of Sir Frank Macfarland Burnet. From 1956 to 1962, Jerne serve as chief medical officer of the World Health Organization (WHO) and then spent four years teaching at the University of Geneva, the University of Pittsburgh, and the J. W. Goethe University. In Pittsburgh, Jerne and Albert Nordin developed the Jerne plaque assay, a now-standard method for counting antibody-producing cells. In 1966, Jerne became director of the Paul Ehrlich Institute in Frankfurt, Germany, where he stayed until 1969. He left to become the founding director of a new institute dedicated to basic research in immunology. INSET: Niels K. Jerne.

Ejnar Hertzsprung was born in Frederiksberg, Denmark, in 1873. His father, Severin Hertzsprung, had studied astronomy at the University of Copenhagen but decided that he could not support his family well by pursuing science. Therefore, he took a position with the Danish government, rising rapidly to director of the state life insurance company. Severin retained his love for astronomy and mathematics, however, and Ejnar became interested in these sciences as well. Although he studied chemical engineering and worked as a chemist after his graduation from college, Ejnar Hertzsprung decided to make astronomy his life's work. In 1902, he began work at the observatory of the University of Copenhagen and at the Urania Observatory in Frederiksberg. In 1905 and 1907, Hertzsprung published two papers that are now considered classics. The title for both was "Zur Strahlung der Sterne," which translates as "on the radiation of the stars." These papers dealt with spectroscopy, the study of which colors (or wavelengths, in the language of physics) make up the light from glowing objects. Hertzsprung showed that stars that have a particular kind of light spectrum are more luminous than the rest. His research laid the foundation for methods of finding the distances to far-off stars and galaxies. Hertzsprung's extensive studies showed him that stars can be classified into two overall categories. He knew the absolute brightness of thousands of stars and from their spectra could determine the temperature of each. In 1911, Hertzsprung made a plot to show the relation of the brightness (or magnitude, in the language of astronomers) to the temperature. On such a plot, stars fall into two overall categories. Most stars fall on what is called the main sequence area of the graph, but some, such as blue giant stars and red dwarf stars, fall on a much different part of the plot. INSET: Ejnar Hertzsprung.

Luigi Galvani (pronounced "gahl-VAH-nee") was born in 1737 in Bologna, Papal States (Italy), to an old and prosperous family. The Galvani family had many ancient ties to the city of Bologna and to its university, and Luigi was never inclined to live elsewhere. Galvani studied medicine at the University of Bologna, obtaining degrees in medicine and philosophy there in 1759. The first years of his professional career were divided between medical practice, research on anatomy; and lecturing in medicine. In 1762 and 1767, he published papers on anatomical studies; the first was on skeletal structure and function, and the latter described the kidneys of birds. In the 1770's, Galvani's interest shifted from anatomy to what is now called physiology: He wanted to understand the function of nerves and muscles. Earlier researchers had described the effect of electrical discharges (sparks) on muscles, and, in 1772, Galvani presented a paper on this subject to the Institute delle Scienze (science institute) of Bologna. INSET: Luigi Galvani.

The early career of Louis-Jacques-Mandé Daguerre (pronounced "dah-GEHR") was as an artist at the Paris Opera in France. He was apprenticed to the chief designer in 1803 and later worked as an assistant to the panorama painter. After his successful exhibit at the Salon in 1814, he worked as an independent stage designer. His set designs were widely acclaimed. In 1822, Daguerre formed a partnership with Charles Marie Bouton, with whom he developed the Diorama. The Diorama consisted of massive pictures painted on both sides of translucent, or transparent, linen. These pictures could be lit from either the top or the rear in order to show the front or back picture. By controlling the lighting, different seasons or times of day were represented. The result was a startling visual effect that fascinated audiences. Bouton and Daguerre established theaters for the Diorama in both Paris and London. In order to create the paintings, Daguerre used a camera obscura, or dark room. The camera obscura was a pinhole camera that used light falling through a small opening to project an image on a screen or sheet of paper. Daguerre became fascinated by the idea of permanently fixing the camera obscura image on paper. In 1826, Daguerre learned of research that Joseph-Nicéphore Niépce was conducting on chemically fixing images. Niépce had already fixed outlines of objects on light-sensitive plates. Daguerre had not yet been successful in his experiments. Niépce and Daguerre became partners in 1829. Niépce had discovered that reverse (or negative) images could be produced using silver chloride to fix the image. He abandoned the process in order to work on producing a direct positive. Daguerre developed a method to reduce exposure time and produced a better lens. INSET: Jacques Daguerre.

The father of Charles-Augustin Coulomb (pronounced "koo-LOHM") was an army officer-turned-tax collector who came from an important family in Montpellier. His mother, Catherine Bajet, came from a wealthy family. (The family name is sometimes given as "de Coulomb," but the use of "de," which implies nobility, is unwarranted. Although the Coulomb family was well connected, no firm evidence exists for a claim to nobility and Coulomb himself never used or claimed a right to such a title.) While he was young, Coulomb's family moved from his birthplace at Angoulême to Paris. There, Coulomb attended lectures at the local colleges. Upon losing his fortune through financial speculation, his father returned to Montpellier. Sometime later, when Coulomb disagreed with his mother about career plans, he also left Paris and joined his father in Montpellier. Coulomb joined the Société des Sciences de Montpellier in March, 1757, and delivered several papers on mathematics and astronomy over the next two years. Coulomb returned to Paris in 1758 for tutoring and then entered the École du Génie, an engineering school in Mézières in February, 1760. He was graduated in November, 1761, with the rank of first lieutenant in the Royal Corps of Engineers. After spending two years at his first assignment in Brest, he was transferred to Martinique in the Windward Islands of the Caribbean. In Martinique, Coulomb supervised several hundred workers as they constructed Fort Bourbon and rebuilt other forts destroyed or damaged by British troops during the Seven Years' War (or the French and Indian War, as it is called in North America). He became seriously ill in Martinique, however, and never fully recovered. In poor health, Coulomb returned to France at the age of thirty-six. In 1773, he published a paper on the strength of materials as related to architecture. INSET: Charles-Augustin Coulomb.

Gustave-Gaspard de Coriolis (pronounced "koh-ryoh-LEES") was born in Paris, France, on May 21, 1792, to a family of nobles. His father was an army officer loyal to Louis XVI. The family fled Paris during the French Revolution, and Coriolis' father became an industrialist. In 1808, the young Coriolis entered the Napoleonic École Polytechnique, which was noted as a training ground for civil servants. At the time of his graduation, he ranked second in his class. After graduation, Coriolis served in the corps of engineers of the École des Ponts et Chaussées, the department of bridges and highways. His poor health and his family's need for a substantial source of income, however, forced Coriolis to leave his post in 1816. In 1816, Coriolis became a tutor in analysis at the École Polytechnique, which would lead to further teaching positions. He continued to teach until 1838, when he became director of studies at the École Polytechnique. Coriolis was appointed to the chair of mechanics at the École Centrale des Arts et Manufactures in 1829. He also published his first book in the same year. Du calcul de l'effet des machines dealt with the definition, calculation, and application of mechanical power. In 1830, when the great mathematician Augustin-Louis Cauchy was exiled, Coriolis was offered Cauchy's chairmanship at the École Polytechnique. Coriolis declined the offer, preferring to continue his work with mechanics. Subsequently, he published a paper on accelerations and the transmission of work that appeared in the school's journal. A second paper followed in 1832. Two years after declining the chair position at the École Polytechnique, Coriolis agreed to work with Claude-Louis-Marie-Henri Navier at the École des Ponts et Chaussées. With Navier, Coriolis engaged in work on applied mechanics. INSET: Gustave-Gaspard de Coriolis.

Eugene Paul Wigner was born in Budapest, Hungary, in 1902. His family was Jewish and reasonably well-to-do, as his father was the manager of one of the leading leather tanneries in the country. The city was undergoing a renaissance during the years preceding World War I and had some of the finest Gymnasia (high schools) in Europe. Wigner was one of the four remarkable scientists--the other three being John von Neumann, Edward Teller, and Leo Szilard--who grew up in Budapest about the same time, emigrated to the United States, and worked on the atomic bomb project; they became known as "the Martians" because of their brilliance. After high school in Budapest, Wigner moved to the Technische Hochschule in Berlin, where he met Albert Einstein, Max Planck, and Wolfgang Pauli and worked under Michael Polanyi. He took his degree in chemical engineering in 1924 and a doctorate in engineering in 1925. Wigner initially returned home to Budapest, where his father procured for him a job in the tannery. He tried to follow his father's wishes, but his love for physics drew him back to Berlin and the excitement of the new quantum mechanics. Wigner wrote papers with several important scientists in Göttingen in the late 1920's and became increasingly interested in applying group theory to quantum mechanics. In 1930, much to his surprise, he was offered a position as lecturer in physics at Princeton University at nearly ten times the salary that he had been receiving in Berlin. INSET: Eugene P. Wigner.

Nikolai Ivanovich Vavilov (pronounced "vuhv-YEE-luhf") was born in Moscow, Russia, in 1887 as the eldest of three children of Ivan Vavilov, a prominent Moscow merchant. All three were encouraged to pursue scientific careers; his brother, Sergei, became a well-known physicist, and his sister, Lidia, was a physician. Nikolai Vavilov pursued a degree in agriculture at the Petrovsko Agricultural Institute in Moscow, being graduated in 1910. After a brief period as an assistant at the Poltava agricultural experiment station, he moved to St. Petersburg to do graduate work. In 1913-1914, he studied in England with pioneer geneticist William Bateson and cereal breeder Rowland Biffen. Vavilov's master of science dissertation, completed in 1914, was on the immunity of plants to infectious diseases. Following his graduation, he taught at the Petrovsko Agricultural Institute. In 1917, Vavilov was appointed a professor of genetics, plant breeding, and agronomy at the Agricultural Institute of Voronezh and the University of Saratov. At a congress of plant breeders that he organized in Saratov in 1920, he presented his classic paper on the law of homologous series in variation, which was also given at the International Agricultural Congress in the United States the following year. INSET: Nikolai Ivanovich Vavilov.

Joseph John Thomson--who would be known throughout his life by family, friends, and colleagues as "J. J."--was born the son of a publisher and bookseller in a suburb of Manchester, England. It was intended that the young Thomson become an engineer and be apprenticed to a maker of steam-driven locomotives, but the waiting list was so long that his father took the advice of a friend and instead sent the fourteen-year-old student to a local college. At Owens College, which in 1880 became Manchester University, Thomson studied mathematics, engineering, and physics under challenging teachers. The early death of his father, however, forced him to reconsider a projected career in engineering, since the cost of the required apprenticeship was beyond his family's means. He therefore studied for an entrance scholarship at Trinity College, at Cambridge University, where he was admitted. Thomson would spend the rest of his life at Trinity. Thomson completed his undergraduate work in 1880 when he took his examinations for the mathematical tripos over nine bleak January days. Among the examiners was the theoretical physicist James Clerk Maxwell, who is best known for his contributions to electromagnetic field theory. Following. the successful completion of these examinations, Thomson wrote a dissertation about energy that resulted in two papers published in the Philosophical Transactions of the Royal Society. Thomson's thesis won for him a fellowship at the university, where he began teaching and initiating a line of research in electrical theory that would point him in the direction of his most important work. It was at this time that he began his association with the recently founded Cavendish Laboratory at Cambridge. The laboratory was virtually unique in its day for providing both equipment and space for teaching and research in physics. INSET: Sir Joseph John Thomson.

Alfred Henry Sturtevant, the youngest of six children, spent his early education in a one-room schoolhouse in Alabama. As a boy, one of Sturtevant's hobbies was to draw the genetic pedigrees of his father's horses and of his own family. In 1908, he entered Columbia University and with the encouragement of his brother, a teacher at nearby Barnard College, began reading books on heredity, thereby stimulating his interest in genetics. Sturtevant submitted his findings on coat color inheritance patterns in horses to noted Columbia University geneticist Thomas Hunt Morgan. Morgan encouraged Sturtevant to publish his findings, which appeared in the Biological Bulletin in 1910, and invited him to join his research group. Morgan's cramped laboratory in which as many as eight scientists worked at one time was called the "fly room." In this rarified atmosphere of excited exchange and debate of scientific ideas, Sturtevant worked with Morgan, H. J. Muller, and C. B. Bridges, among others. While still an undergraduate student, Sturtevant developed the first chromosome map of Drosophila melanogaster, the fruit fly, and introduced the concept of using the frequency of crossing-over of linked genes as a means to construct such a genetic map. Sturtevant's doctoral work was completed in 1914, and he remained at Columbia in the "fly room" conducting research until 1928. During this time, Sturtevant published works that significantly advanced the field of genetics, including a 1925 paper entitled "The Effects of Unequal Crossing Over at the Bar Locus in Drosophila," which detailed the phenomena of unequal crossing-over of chromosomes during meiosis and of position effect in the expression of genes. INSET: Alfred H. Sturtevant.

Maarten Schmidt was born on December 28, 1929, in Groningen, the Netherlands. It was Schmidt's uncle, an amateur astronomer, who introduced him to the joys of observing the skies. One summer at his grandfather's house in the country, Schmidt found a large lens, which he then combined with an eyepiece, using a toilet paper roll as a spacer, to make a telescope. His uncle told him to try to resolve a double star to test his telescope. Schmidt had to get a book on astronomy to look up the location of the star and became interested in what the book had to say. Although concerned about his prospects in this field, since there were few positions in astronomy in the Netherlands at that time, Schmidt's parents were always supportive and encouraged his interest in astronomy. Schmidt became an avid stargazer; the blackout conditions of World War II were perfect for making observations. As a result of this early experience, Schmidt later became known to his colleagues as a "good eye," someone who worked a telescope well--a talent that would later pay off. When Schmidt entered the University of Groningen in 1946, he knew that he wanted to study astronomy. His interest at first lay in the study of the Milky Way. His initial area of study was an observation of one of the spiral arms. For his thesis, he prepared a mass model of the Galaxy. INSET: Maarten Schmidt.

Matthias Jakob Schleiden (pronounced "SCHLI-dehn") grew up in Hamburg, Germany, where his father was a prominent doctor. As a young man, he studied law and then practiced from 1827 until 1831. Schleiden was unhappy and unsuccessful as a lawyer. He became depressed and ended his legal career by shooting himself in the head. Schleiden survived to begin a new life in science by going to Berlin in 1833 to study with physiologist Johannes Müller. Using the compound microscopes that had become available in the 1830's, Schleiden observed how plants grow and take form and realized the importance of cells. He discussed his findings with Müller's assistant, Theodor Schwann, who did similar work on animals, and together they developed the cell theory. Schleiden's version of the theory appeared in the paper "Beiträge zur Phytogenesis" (1838). Translated into French in 1839 and into English in 1841 as "Contributions to Phytogenesis," it established his international reputation. In 1839, Schleiden moved to the University of Jena in the German state of Saxe-Weimar, where he received his Ph.D. and began to teach. There, he wrote his textbook Grundzüge der wissenschaftlichen Botanik (1842; Principles of Scientific Botany as an Inductive Science, 1849), in which he discussed cell theory, microscopy, and scientific method. In this and other writings, he attacked or ridiculed anyone who did not live up to his methodological standards. Even though he insulted some leading scientists, Schleiden received an honorary degree in medicine and was elected to scientific academies all over Europe in the 1840's. By 1850, he was full professor of botany and director of the botanical gardens at Jena and had the title of court counselor to the grand duke of Saxe-Weimar INSET: Matthias Jakob Schleiden.

Chandrasekhara Venkata Raman was born in Trichinopoly (now Tiruchchirappalli), Madras, India, on November 7, 1888. It was a time of considerable intellectual, artistic, and creative resurgence in India. A sense of national awakening against the British colonial occupation was beginning to unite the diverse regions of the country, and the resulting nationalistic impetus manifested itself in literature, music, art, and science. Srinivasa Ramanujan, the mathematical prodigy, was born the preceding year, and the decade following Raman's birth witnessed the birth of such scientists of world stature as mathematician and physicist Satyendranath Bose and astrophysicist Meghnad Saha. Raman was the second of eight children born to Ramanathan and Parvati Chandrasekhar. Despite much hardship, Raman's father obtained his B.A. degree and continued his studies of literature, mathematics, and physics while teaching as a high school teacher with a modest income. Raman's early interest in physics was sparked by the ready availability of fine books in his father's library. Raman and older brother Chandrasekhara Subrahmanyan Ayyar, the father of the astrophysicist Subrahmanyan Chandrasekhar-Subrahmanyan], received their primary education in Tamil, English, and arithmetic from their father. They attended a college in Vizagapatam of which their father was the vice principal, and both proved to be brilliant students. Raman was graduated from high school at eleven, completed college at fifteen, received his master's degree at seventeen, and earned the highest score in the All-India Competitive Examination for civil servants at eighteen. In 1907, Raman joined the Indian Finance Department in Calcutta as assistant accountant general, working there for ten years. During this time, he carried out extensive research in his spare time and published no fewer than thirty papers in leading journals. INSET: Sir Chandrasekhara Venkata Raman.

Linus Carl Pauling was born in Oregon in 1901. His father, a pharmacist, guided the reading of his inquisitive young son, but his death in 1909 left the family economically and emotionally devastated. Linus studied mathematics and chemistry at Washington High School in Portland, but what convinced him to become a chemist was a dramatic experiment performed by a classmate in his bedroom laboratory. Pauling's educational career at Oregon Agricultural College was interrupted by financial difficulties, but, through persistence and hard work, he managed to graduate with highest honors in 1922. During his graduate studies at the California Institute of Technology (CIT or Caltech), he married Ava Helen Miller; their marriage resulted in three sons and a daughter. Pauling received his doctorate in 1925. Following a period of postdoctoral studies, he accepted a Guggenheim Fellowship in 1926 to study the application of the new quantum mechanics to chemical problems. He spent most of his time in Europe at Arnold Sommerfeld's Institute for Theoretical Physics in Munich, Germany. He returned to California in 1927 and began his long career as a teacher and researcher at CIT. He was prodigiously successful, becoming a full professor in 1931 and head of the Division of Chemistry and Chemical Engineering in 1937. Structure was the chief theme of Pauling's scientific work. In his early research, he used the X-ray diffraction technique to determine the structures of such crystals as molybdenite (his first scientific paper) and various silicates and sulfides. In 1930, he began using the electron-diffraction technique for exploring the structures of such molecules as benzene and cyclohexane. As X-ray and electron diffraction gave Pauling experimental tools for discovering the structures of molecules, so quantum mechanics provided him with a theoretical tool. INSET: Linus Pauling.

Wolfgang Ernst Pauli was born on April 25, 1900, in Vienna, Austria. His father, Wolfgang Joseph Pauli, was a physician who became a well-known biochemist at the University of Vienna. His mother, Bertha, was a writer who had many friends in the worlds of the theater and the press. Young Wolfgang's second name was given in honor of Ernst Mach, the noted professor of theoretical physics who was his godfather. During World War I, Pauli was a pupil in the Gymnasium of Dobling in Vienna and was recognized as a child prodigy in physics and mathematics. His father frequently obtained from Mach titles of physics and mathematics articles and books for Wolfgang to read. By the time of his graduation from the gymnasium, he was prepared to write three papers on relativity theory, which were published in 1919. Pauli chose to study theoretical physics with Arnold Sommerfeld in Munich. Sommerfeld recognized and nourished the budding genius of his pupil. He asked Pauli, who was then nineteen years old, to write in his place an encyclopedia article on relativity theory, which was published in 1921. This article established Pauli's reputation and remains a valid account of the subject. He received his doctorate the same year summa cum laude from the University of Munich. INSET: Wolfgang Pauli.

James Clerk Maxwell was born at his family's estate in Dumfrieshire, Scotland, where he spent his first ten years. Although the original family name was Clerk, James's father added "Maxwell" after inheriting the estate from his Maxwell ancestors. Trained as a lawyer, Maxwell's father never practiced extensively but spent his time studying architecture and tinkering with mechanical gadgets. Since James's youth was spent remote from any school, his education was entirely in his mother's hands. She taught him reading and writing, motivated his curiosity, and encouraged his prodigious memory. In 1839, when Maxwell was eight, she died, abruptly ending his idyllic lifestyle as well as his education. For the next two years, a tutor was employed, but the results were disastrous. Mr. Maxwell enrolled his ten-year-old son at Edinburgh Academy. Although James did badly at first, he soon began to excel in mathematics, receiving the annual mathematics award at the age of thirteen. The following year, his father began taking him to meetings of the Edinburgh Royal Society. At the age of fourteen, Maxwell discovered a new mathematical method for forming ovals; his results were presented to the society in March, 1846. A pivotal point in Maxwell's youth was the memorable afternoon in April, 1847, when his uncle took him to visit the private laboratory of physicist William Nicol. Enthralled by the demonstrations of experiments in progress, Maxwell set his course on becoming a physicist. In November of the same year, he enrolled at the University of Edinburgh, where he spent the next three years developing his mathematical skills and writing two more papers for the Royal Society. Maxwell entered Cambridge University in October, 1850. His brilliance was recognized early by his teachers, and he was elected a scholar at Trinity College after his second year. INSET: James Clerk Maxwell.

Konrad Zacharias Lorenz (pronounced "LOHR-ehnts") was born in Vienna in 1903. He was the younger of two sons born to Emma (Lecher) Lorenz and Adolf Lorenz. His father, the son of a harness maker, rose from poverty to become a wealthy orthopedic surgeon. Throughout his childhood, Lorenz was extremely interested in animals. He had many pets, kept detailed diaries of his observations on animal behavior, and nursed sick animals at the Schöbrunner Zoo in Vienna. Lorenz's early education was at a private school conducted by his aunt; afterward, he entered the prestigious and rigorous Schottengymnasium. When he finished high school, Lorenz wished to study zoology and paleontology, but he obeyed his father, who wanted him to study medicine. Lorenz studied medicine for a year at Columbia University, in New York City, and then returned to the University of Vienna to finish his medical studies. He recognized the relationship between areas of his medical studies and that of animal behavior, which remained his preferred research focus throughout his life. One of earliest papers described the behavior of the jackdaw, a crowlike bird, and was published in the prestigious German Journal of Ornithology. INSET: Konrad Lorenz.

Joseph Lister was born in a small village east of London in 1822. His father, Joseph Jackson Lister, was a wealthy wine merchant and a self-educated man versed in both mathematics and optics. The love of science was passed on to the younger Joseph, the second son in the household. Even at a young age, Lister demonstrated a general interest in nature. Having completed his early education in the Quaker school at Tottenham, Lister enrolled at University College in London at the age of sixteen. In December, 1846, as a nineteen-year-old undergraduate student, he was present when Robert Liston, a professor of surgery at University College, carried out the first surgical operation under ether in Europe. Following his graduation in 1847, Lister entered the medical program at University College. While still a student, he presented two papers, "Gangrene," and "Use of the Microscope in Medicine," in front of the Hospital Medical Society. Lister was graduated with honors in 1852. In 1852, Lister served a term as house physician, followed by nine months of service as a house surgeon. His interest in surgery as a career led Lister to move to Edinburgh in 1853, where he developed both a professional and a personal relationship with James Syme, one of the outstanding technical surgeons in England. The outbreak of the Crimean War in 1855 led Lister to apply for a vacant position as staff surgeon at Edinburgh, and, in April, 1855, he was appointed assistant surgeon to the Edinburgh Royal Infirmary and lecturer in surgery to the Royal College of Surgeons. It was at this time that he began courting Syme's daughter, Agnes, whom he married in 1856. INSET: Joseph Lister.

William Thomson, later known as Lord Kelvin, was the son of James Thomson, a professor of engineering, who taught William at home during his childhood in Belfast, Ireland. James Thomson accepted a professorship at the University of Glasgow in 1832, and William was enrolled at that university when he was only eleven. At sixteen, he won a medal for an undergraduate essay on the figure of the earth that applied principles of physics and mathematics, not geology. This foundational, analytic approach characterized his work thenceforth. Under Professor William Meickleham and others, Thomson read and developed an appreciation for brilliant continental analysts such as Joseph-Louis Lagrange. At fifteen, he understood Joseph Fourier's theory of heat, the celestial mechanics of Pierre-Simon Laplace, and Lagrange's analytical mechanics. He mapped an attraction in an electric fluid problem into a heat flow problem, finding the behavior of these systems equivalent, which resulted in his first scientific paper. At Cambridge University, he curtailed these deeper insights for a more rigid and rigorous pursuit of grades. Nevertheless, he kept abreast of continental analysis. Peterhouse was less rigid than other parts of Cambridge and accepted Thomson without a formal degree from Glasgow. His tutor, William Hopkins, was the best mathematics coach at Cambridge, genuinely interesting to students, and understanding of Thomson's unique ability. Hopkins recognized that while Thomson 'was not the best at examinations, he had a broader, more analytic mind, capable of original thought. Thomson also met Sir George Gabriel Stokes, beginning a lifetime of numerous correspondences, with Thomson synthesizing and Stokes critically refining. In 1845, Thomson was graduated from Cambridge. Seeing dismal job prospects, he went south, to Paris. INSET: Lord Kelvin (Sir William Thomson).

Sir Fred Hoyle was born in Bingley, England, in 1915. His mother, a former schoolteacher, and his father, a cloth merchant, were determined that he receive a good education, an ambition that young Hoyle did not share. Frequent truancy from ages ten to twelve, he later claimed, allowed him to explore science on his own. Nevertheless, Hoyle finished the English equivalent of high school and won a scholarship to Cambridge University in 1933, where he studied mathematics. He was graduated in 1936 and stayed at Cambridge to study physics with Rudolf Peierls and Paul A. M. Dirac, both leading theorists. He received a master's degree in 1939 and married Barbara Clark, with whom he had a son, Geoffrey, and a daughter, Elizabeth. Hoyle was about to begin a fellowship at St. John's College, Cambridge, when World War II started; instead, he helped modify radar to detect aircraft and submarines for the Royal Navy. Hoyle resumed his Cambridge fellowship as a lecturer in the mathematics faculty in 1945, where he quickly gained a reputation as an energetic, unconventional thinker. Despite a heavy teaching load, he developed a theory, begun during the war with Maurice Pryce, to explain the production of light elements in stars. He also predicted an energy state of carbon that had never been detected (experiments soon proved him correct) and pointed out that more helium existed in the universe than could be accounted for by theory. During the late 1940's and 1950's, Hoyle spent several terms at the California Institute of Technology and at the Mount Wilson and Mount Palomar Observatories. He worked closely with Margaret Burbidge, Geoffrey Burbidge, and William A. Fowler to explain how supernovas form heavy elements. Their collaboration culminated in a landmark paper in astrophysics, "The Synthesis of Elements in Stars" (1957). INSET: Sir Fred Hoyle.

Joseph Henry was born in Albany, New York, in 1797. His father was an alcoholic, and Henry was reared by an uncle and his maternal step grandmother. At the age of eighteen, he read a popular introduction to science, which excited him about the subject. He decided to become a scientist. From about 1815 to 1826, Henry worked as an actor, a country schoolteacher, a tutor, and a surveyor He attended the Albany Academy as an older student from 1819 until 1822. In 1826, he was chosen as professor of mathematics and natural philosophy (physics) at the Albany Academy. While at the Albany Academy; Henry began his lifelong effort to understand the relationships between electricity, magnetism, light, and heat. During this period, he focused on the relationship between magnetism and electricity, especially the creation of an electric current by a changing magnetic field. With a heavy teaching load, Henry had limited opportunities to experiment. Nevertheless, beginning in 1827, he published a number of papers. The most important are those in which he described the first electric motor, in 1831, and mutual electromagnetic induction and electromagnetic self-induction, in 1832. He demonstrated the electromagnetic telegraph to his students in 1831. During these years, Henry often published in response to the announcement by European scientists of discoveries that parallelled or anticipated Henry's research. He was always in danger of losing his claim of priority or of being ignored by the European community. This was especially true of his work on induction, as Michael Faraday was working simultaneously on the same topic.

Werner Karl Heisenberg (pronounced "HI-zehn-berk") was born on December 5, 1901, in Würzburg, Germany. His father was a teacher of classical languages who eventually became a professor at the University of Munich, where he moved his family in 1910. Werner completed his primary education at the Elisabethenschule in Munich, then attended the Maximilians-Gymnasium until his graduation in 1920. After surviving a serious case of typhoid in the summer of 1920, Heisenberg received a scholarship and entered the University of Munich as a student of the physicist Arnold Sommerfeld. His preparation had been excellent,Receiving his doctorate in 1923, Heisenberg worked for a time as an assistant to Max Born at the University of Göttingen. From 1924 to 1926, he worked with Niels Bohr in Copenhagen, supported by a Rockefeller Foundation grant. During this period, Heisenberg invented matrix mechanics, the first complete formulation of quantum mechanics. His brilliant successes won for him a professorship in theoretical physics at the University of Leipzig at the age of twenty-six. and he soon began publishing research papers. INSET: Werner Karl Heisenberg.

Stephen Jay Gould was born in New York City in 1941. At the age of five, he visited the American Museum of Natural History in New York City. The displays of dinosaur eggs, bones, and mounted skeletons provided a foundation for his later interest and research in the science of paleontology; the study of fossils and ancient life forms. Gould completed his primary and secondary education in New York City schools. At Antioch College, in Yellow Springs, Ohio, he earned an A.B. degree in 1963. In 1967, he earned a Ph.D. degree in paleontology at Columbia University and accepted a position as professor of geology at Harvard University; in Cambridge, Massachusetts. Gould supported Charles Darwin's hypothesis of evolution but did not see smooth transitions from one species to another. He became an outspoken critic of uniformitarianism--the doctrine that geophysical agents have been more or less constant over geologic time. In 1972, Gould and Niles Eldredge published a paper on the concept of punctuated equilibrium. Punctuated equilibrium postulates that evolution occurs at irregular intervals of time: long periods with little change in species, followed by bursts of species transformation. This is the opposite of Darwin's theory that evolution is a gradual, smooth progression. Some paleontologists labeled these bursts of transformation and speciation as "little creations." Gould and Eldredge offered their theory as an alternative to Darwin's theory of natural selection. They argue that gradualism exists but that punctuated equilibrium is demonstrated frequently in the fossil record. INSET: Stephen Jay Gould.

Josiah Willard Gibbs was born in New Haven, Connecticut, in 1839, the only son in a family of five children. His father, also named Josiah Willard Gibbs, was a noted philologist and professor at Yale University. The younger Gibbs would himself be associated with Yale for most of his life. In the late 1850's, Gibbs attended Yale, where he won prizes in Latin and mathematics before graduating in 1858. He continued his studies there and, in 1863, received a doctorate in engineering, one of the first advanced degrees awarded in the United States. By this time, his parents and two of his sisters had died. Gibbs decided to further his education by traveling to Europe in the company of his two remaining sisters. He spent the next three years attending lectures on physics and mathematics at universities in Paris, Heidelberg, and Berlin. During this time, Gibbs' interest slowly shifted from engineering to pure science. In 1869, Gibbs returned to the United States. Two years later, he was appointed professor of mathematical physics at Yale, and he began his first significant scientific work shortly thereafter. In 1873, Gibbs published two papers that provided the first solid mathematical basis for thermodynamics, the branch of physics involving the study of heat and mechanical action. INSET: Josiah Willard Gibbs.

Enrico Fermi (pronounced "FEHR-mee") was born in Rome. His father was an official of the Italian railroad, and his mother was a schoolteacher. He was an excellent student and liked to memorize poetry. He enjoyed outdoor activities such as hiking, tennis, and skiing. A friend of the family recognized Fermi's unusual academic talent and supplied the teenager with a progression of books on mathematics and science, going far beyond the public school curriculum. At the age of seventeen, Fermi entered the competition for a fellowship to the University of Pisa, for which he had to write a paper on sound waves. Starting with a differential equation, he obtained solutions for the resonant frequencies of a vibrating reed. He won the fellowship. After only four years at Pisa, Fermi received a Ph.D. in physics with highest honors. In order to augment his knowledge of quantum mechanics and modern physics, Fermi obtained a postdoctoral fellowship, which enabled him to work under some of the leading physicists of the time at Göttingen, Germany, and Leiden, the Netherlands. Such a period of apprenticeship was intended to give a young scientist an overview of the current frontiers of research. INSET: Enrico Fermi.

Paul Ralph Ehrlich, the son of William and Ruth (Rosenberg) Ehrlich, was born in Philadelphia, Pennsylvania in 1932. His early inspiration to study ecology came when he read William Vogt's Road to Survival (1948) in high school. This book alerted Ehrlich to the problem of rapid population growth and insufficient food production. Ehrlich's early academic work in biology concentrated on entomology, the study of insects. He studied the effects of DDT on insect survival and then intensified his work on butterflies for his Ph.D. research. His early papers on checkerspot butterflies (Euphydryas editha) dealt with their population ecology and genetics. After receiving his Ph.D. in 1957, Ehrlich continued his entomology research in Kansas. One of the first of the many books that Ehrlich published was How to Know the Butterflies (1961). Although much of his research was done in entomology; unchecked human population growth and its devastating effects on the environment soon became his main concern. Ehrlich believed that humankind would reproduce itself into oblivion. The environmental problems and crises of the 1960's provided the main arena in which Ehrlich and his wife Anne Howland Ehrlich would make their greatest contributions to solving the environmental challenges that humankind is facing. Ehrlich became an assistant professor of biology in the department of biology at Stanford University in 1959. He was promoted to associate professor in 1962 and full professor in 1966. He and his wife became leaders of the international movement for population control, fearing that millions would starve to death as the result of overpopulation. In 1968, they helped found the organization Zero Population Growth (ZPG), which worked to stop the explosive growth of human numbers. INSET: Paul R. Ehrlich.

Jean Baptiste Gabriel Joachim Dausset (pronounced "doh-SAY") was born in Toulouse, France, and went to high school at the Lycée Michelet in Paris. In the 1930's, he attended the University of Paris medical school before being drafted into the French army. In the early 1940's, Dausset was in North Africa fighting German troops with the Free French forces during World War II. Before going to North Africa, he helped a Jewish colleague at the Institut Pasteur hide from the Nazis by giving him his identity papers. In North Africa, Dausset worked in a resuscitation unit, where his experience in blood transfusions sparked an interest in immunohematology. Dausset earned his M.D. from the University of Paris in 1945, the same year that he left the army. In 1946, at only thirty, he became director of laboratories at the national blood transfusion center. Dausset then went to Harvard University in 1948 to study hematology and immunohematology for two years. In the late 1940's, Dausset conducted extensive research on blood transfusions. In 1951, he discovered that strong immune (anti-A) antibodies could develop in type O blood from donors who had been vaccinated for diphtheria or tetanus. Up to that time, type O blood had been regarded as safe for individuals with all other blood types. Dausset's research initiated systematic blood testing for both donors and transfusion patients, thereby preventing dangerous reactions such as clotting. INSET: Jean Dausset.

John Dalton was born on or about September 6, 1766, in Eaglesfield, Cumberland, England. His father, Joseph, was a weaver and a devout Quaker. As a boy, Dalton was educated at a local Quaker school, but in his early teens he was forced to work as a common laborer to support himself. In 1781, Dalton was hired to replace his older brother as an assistant in a boarding school in Kendal, forty miles from his home. His new position gave him access to the school's facilities, including the library and the collection of scientific equipment. He was also able to attend lectures by notable visitors to the region. During the next few years, Dalton was given increasing responsibilities at the boarding school. As was common at the time, he began offering public lectures in astronomy, mechanics, and other areas of science. Yet, Dalton found himself limited by life in a small town. In 1792, he moved to Manchester, where he obtained an appointment as a professor of mathematics and natural philosophy at the New College. In 1793, Dalton published a series of observations and essays on meteorology. The next year, following his election as a member of the Manchester Literary and Philosophical Society, he presented a paper containing the first detailed discussion of color blindness, an affliction from which Dalton himself suffered. While his explanation for the cause of color blindness turned out to be incorrect, the condition is sometimes called daltonism in honor of his work on the subject. As part of his teaching duties at the New College, Dalton was required to lecture on chemistry. His interest in chemistry and meteorology led him to consider the behavior of mixtures of gases. In 1801, he proposed that in a mixture of gases, each component acts independently of the other gases present. This behavior, true for mixtures of ideal gases, is now known as Dalton's law of partial pressures. INSET: John Dalton.

As a boy, David Brewster studied the physical sciences and built telescopes, sundials, and microscopes. The son of a Scottish rector, he entered the University of Edinburgh in 1794 aspiring to a career in the clergy. A nervous disposition and an extreme fear of public speaking, however, led Brewster to pursue his love of science instead. Working as a private tutor from 1799 to 1807, Brewster also began his long career in editing in 1802. He failed several times to gain university professorships in Scotland, and his primary income came from editing scientific journals such as the Edinburgh Philosophical Journal, the Edinburgh Journal of Science, and the Philosophical Magazine. While still a student, Brewster began his extensive optical research. Of his thirty papers published in the Philosophical Transactions of the Royal Society, all involved optics. A tireless experimenter, Brewster investigated such phenomena as polarization, double refraction, and metallic reflection. He also invented the kaleidoscope, established Brewster's law, and helped create the fields of optical mineralogy and photoelasticity. He was highly regarded by his contemporaries, who called him the "Kepler of optics" and the founder of modern experimental optics. INSET: Sir David Brewster.

The son of a lawyer, Stanislaw Marcin Ulam (pronounced "EW-lahm") was born in 1909 in the town of Lwów (or Lemberg), Poland, which at that time was in the Austrian Empire. He was fascinated by mathematics and by Albert Einstein's relativity theories. At the age of twenty, he published his first mathematical paper. He attended the Polytechnic Institute in Lwów and obtained his doctorate in 1933. In 1936, the famed mathematician John von Neumann invited Ulam to join the Institute for Advanced Study in Princeton, New Jersey. In 1941, Ulam became a U.S. citizen. In February, 1944, as World War II raged overseas, von Neumann brought Ulam to the heart of the top-secret Manhattan Project in Los Alamos, New Mexico. Its aim was to invent an atomic bomb. Meanwhile, working under physicist Edward Teller, Ulam investigated the feasibility of building an even more powerful hydrogen bomb. The first atomic bomb was exploded in July, 1945. To develop nuclear weapons, scientists made extremely complex calculations based on high-speed interactions of numerous subatomic particles. They used an early, slow generation of electronic computers. In 1946, Ulam thought of a way to hasten the calculations. While recovering from the illness encephalitis and playing the card game solitaire, he realized that he could better anticipate the outcome of his game by making intelligent bets based on a few cards, rather than on his entire hand. Likewise, he could simplify and speed nuclear calculations by basing them on the behavior, or "life histories," of a small sample of typical particles. With von Neumann, Ulam developed this technique, later called the Monte Carlo method after the casino resort. INSET: Stanislaw Ulam.

Albert Szent-Györgyi (pronounced "saynt JAHR-jee"), in full Albert Imre Szent-Györgyi von Nagyrapolt, was born in Budapest on September 16, 1893. At the age of eighteen, he entered medical school at the University of Budapest and began scientific research in his freshman year. Following family tradition, his early research dealt with anatomical topics, and, before he received his medical degree in 1917, he had already published several scientific papers. World War I caused Szent-Györgyi to leave medical school to serve in the Austro-Hungarian army on both the Russian and Italian fronts. He was wounded and decorated for bravery. After the war, Szent-Györgyi had a large number of professional positions at several European universities and the Mayo Clinic in the United States. Those experiences put him in contact with many scientists whose interests were the chemical processes inside the cells of living creatures. As a result, he obtained another degree, a Ph.D. in chemistry and physiology from Cambridge University. With a primary interest in research, a medical background, the ability to ask the right questions, a charismatic demeanor, and a background in several scientific disciplines, SzentGyörgyi entered the field of cell biology at a time when major discoveries were being made. He contributed to these discoveries with the isolation of vitamin C. In 1932, he became the chair of the department of medical chemistry at the University of Szeged, Hungary. In 1937, he was awarded the Nobel Prize in Physiology or Medicine for "discoveries in connection with the biological combustion processes, with special reference to Vitamin C and the catalysis of fumaric acid." Another war affected Szent-Györgyi's career just as he had begun research on muscle physiology. INSET: Albert Szent-Györgyi.

Frederick Soddy was the last of seven children born to Benjamin Soddy, a successful London corn merchant, and Hannah (Green) Soddy. Frederick's mother died less than two years after his birth, and he was reared by an older sister. The family held strong Calvinist beliefs that, even though rejected by Soddy as an adult, seem to have shaped his attitudes about getting at the truth. Soddy showed no interest in science until he came under the influence of the science master at Eastbourne College. Together with his mentor, Soddy published his first scientific paper at the age of seventeen. He entered Merton College at Oxford University in 1896 and was graduated with first-class honors in chemistry two years later. After two more years of study at Oxford, Soddy applied for the post of professor of chemistry at the University of Toronto in Canada and, without waiting for a response, traveled there to further his application in person. When he found no chance of success, he set out for home but stopped on the way at McGill University in Montreal. There, in May, 1900, he accepted the position of junior demonstrator in chemistry. By September, he had met Ernest Rutherford, a professor of physics at McGill. With their combined knowledge of chemistry and physics, they embarked on a joint study of thorium and other recently discovered radioactive elements. INSET: Frederick Soddy.

Nikolai Nikolayevich Semenov (pronounced "sih-MYOH-nuhf") was born in Saratov, Russia, on April 15, 1896. He completed his secondary education there and then enrolled at Petrograd University, where he studied chemistry from 1914 to 1917, completing his degree on the eve of the Bolshevik Revolution. Semenov taught chemistry in Tomsk, western Siberia, during the troubled civil war period and in 1920 returned to Petrograd (later St. Petersburg, then Leningrad, and then St. Petersburg again). He taught chemistry at the Petrograd Polytechnical Institute and conducted research at the Petrograd Physical-Technical Institute, where he was director of the Electron Phenomenon Laboratory. He married Natalia Burtseva in 1924; the couple had two children. In 1924, Semenov became involved in the research of Yuri Khariton and Z. Val'ta, who were investigating the oxidation of phosphorus vapor. This explosive reaction displayed a number of anomalous features that could not be explained by the simple kinetic model (Arrhenius' law) in use at the time. Semenov was able to formulate a model that explained these anomalous features by postulating that a chain reaction was involved. He published his results in 1928 in the landmark paper "K teorii protsessov goreniyaa, Soobsch. i" (toward a theory of combustion processes, part 1). INSET: Nikolai Semenov.

Karl Schwarzschild (pronounced "SHVAWRTshihlt") was born on October 9, 1873, as the son of a prominent Jewish businessman, Moses Martin Schwarzschild, and his wife, Henrietta Sabel. Karl grew up in his hometown of Frankfurt am Main, where he enjoyed the benefits of a highly cultured civic and family life. His early education was parochial, but he attended high school at the municipal preparatory school, or Gymnasium. There, he became actively interested in astronomy and was encouraged in his pursuits by his father, who knew a local mathematician with a private observatory. By the age of sixteen, Schwarzschild had published two papers on the orbits of double stars. After the Gymnasium, he spent two years at the University of Strasbourg, then an important center for astronomy and related studies. In 1893, he entered the University of Munich, receiving his doctorate there in 1896. Schwarzschild took a job as assistant in the Kuffner Observatory near Vienna that year and remained until the summer of 1899. He then began giving lectures on astronomy for general audiences, serving as a docent at Munich for two years. His first professorship was at the University of Göttingen, beginning in 1901. INSET: Karl Schwarzschild.

Wilhelm Conrad Röntgen (pronounced "REHNT-guhn") was born in Lennep, Prussia, in 1845. His father was a cloth merchant, and his mother was from the Netherlands; Wilhelm was their only child. The family moved to Apeldoom, the Netherlands, when Röntgen was only three. He attended local public schools there until the family moved later to Utrecht. He was a bright, active child, who loved to roam the fields and hills near his home. Röntgen continued his education in the Netherlands until 1865, when he enrolled in the mechanical engineering program at the Polytechnic Institute in Zurich, Switzerland. At the institute, he studied with two famous physicists: Rudolf Clausius, who formulated the second law of thermodynamics, and August Kundt, who became Röntgen's mentor. After Röntgen earned his Ph.D. from the Swiss Polytechnic Institute, he stayed on as Kundt's assistant and then followed Kundt as an assistant to several universities in Germany. A productive researcher and writer, Röntgen had already published forty-eight scientific papers by 1895, the year that he discovered X rays. INSET: Wilhelm Conrad Röntgen.

Jean-Baptiste Perrin (pronounced "peh-RAN") grew up in a modest home, reared along with two sisters by his mother. He attended high school in Lyons and Paris, France, then left for service in the army. Within a year, however, Perrin's skill in mathematics enabled him to gain university admittance to the École Normale Supérieure. Perrin was among the first students in a new study called physical chemistry. Physical chemists wished to organize into general laws, like those used in physics, the array of descriptive statements that chemists had made about individual compounds and their reactivities. Most physical chemists thought that the best path to this end was thermodynamics, the study of the transfer of energy in chemical reactions, because energy changes could be quantified and measured. Such a strategy; however, ignored analysis of the individual molecules and atoms that chemists since John Dalton in the early nineteenth century had assumed were the building blocks of individual substances. Perrin's interest in attacking the problems of physical chemistry from this "atomistic" standpoint can be seen in his first published paper in 1895, in which he demonstrated that cathode rays are negatively charged by collecting and recording their presence within a wired metal cylinder. Perrin coupled this study with experiments on the newly discovered X rays in his Ph.D. thesis in 1897. INSET: Jean-Baptiste Perrin.

Lars Onsager was born in Kristiania (now Oslo), Norway, in 1903. His family was middle class, and he grew up in comfortable surroundings. Following his graduation from secondary school, Onsager enrolled at the Norwegian Technical School in Trondheim, where he studied chemical engineering. It soon became clear that Onsager had a talent for science. In 1925, he traveled to Zurich, Switzerland, to discuss with noted physical chemist Peter J. W. Debye a correction that Onsager had found to Debye's theory of electrolytes in solution. Debye decided to take Onsager on as a research assistant. After two years in Switzerland, Onsager emigrated to the United States, where he had landed a job as an instructor in freshman chemistry at The Johns Hopkins University. Shortly thereafter, he moved to Brown University, where he continued to teach while conducting research. Onsager remained at Brown from 1928 to 1933. During this period, he worked on the problem of reciprocal relationships. Examples of these types of relationships had been known for more than a hundred years, but Onsager was able to develop a general theory that provided a systematic description for such relationships. Onsager's theory on reciprocal relationships was outlined in two papers published in 1931. He showed that for small departures from equilibrium, simple relationships can be found to describe the approach to equilibrium. Onsager's work soon found a variety of applications in nonequilibrium thermodynamics (the study of heat). Onsager himself used his theory to analyze thermal diffusion as a means for isotope separation. In the early 1940's, this work formed the basis for one separation method used to isolate the uranium 235 isotope in the development of the atomic bomb. INSET: Lars Onsager.

Tsung-Dao Lee, the third of six children, was born the son of a businessman. After middle school, he entered the National Chekiang University in 1943, but the invasion of Japanese troops necessitated evacuation to Kunming, where he attended the National Southwest Associated University. There, he studied with Ta-You Wu, who procured a Chinese government fellowship for Lee and took him to the United States in 1946. Lee had difficulty entering a graduate program, having completed only his sophomore year. The University of Chicago, however, accepted students without formal degrees if they were familiar with certain "great books." Lee was able to convince the admissions officer that he was knowledgeable in the Chinese equivalent of these Western classics, and he was accepted. Chicago probably had the best science department at that time, with a distinguished faculty and equally talented students. One of these was Chen Ning (Frank) Yang, whom Lee had met in Kunming. The two became close friends. In 1948, Lee began his doctoral thesis, on white dwarf stars, under the great physicist Enrico Fermi. In 1950, he completed his Ph.D. and married Hui Chung (Jeannette) Chin; they would have two sons. After working with astrophysicist Subrahmanyan Chandrasekhar at the Yerkes Observatory for eight months, followed by one year at the University of California, Berkeley, Lee spent two years at the Institute for Advanced Study at Princeton University, where Yang had a position. Lee and Yang published two important papers in statistical mechanics. Lee became an assistant professor at Columbia University in New York in 1953 and was promoted to full professor in 1956, the youngest on the Columbia faculty. Lee was associated with Columbia University for almost his entire scientific career. INSET: Tsung-Dao Lee.