This bulletin is virtually a new edition of the work entitled "Special collections of American libraries," by William Coolidge Lane and Charles Knowles Bolton, published in 1892. Since the publication of that most important contribution to American library literature there have been several surveys of a local character published. While these surveys are of fundamental importance, in the scientific organization of our libraries a national survey is of even greater importance, because it is only by such a survey that collections of general value may be distinguished from those of merely local value and that the results of all local surveys may be generally known. It was for these reasons that the Commissioner of Education, in collecting the library statistics of the year 1908, determined to secure also information regarding special collections in libraries in the United States, and with that in view issued a circular, dated November 2, 1908, asking librarians to describe (1) any collections of books, pamphlets, periodicals, and documents in their libraries which were of unusual value either because of their completeness in foreign literature or early literature of a subject or because the works in them were monumental in character or of unusual rarity; (2) collections of interest primarily because of their history and associations; (3) unique copies of any book. This circular was sent to 2,298 libraries. In preparing the returns for publication very much has, of course, been omitted, and perhaps more might have been omitted with profit. It seemed better, however, to err on the side of inclusiveness. It also seemed better to arrange the material by subject matter rather than by place, although this plan involved more editorial labor. It should be added that these statistics, like others, must, in the nature of things, be only relatively correct, because some libraries, like the Library of Congress and the John Crerar Library, are growing very rapidly, and because libraries differ more or less in their classification of books. Subject areas covered in this directory of special collections include: (1) General Collections; (3) Philosophy; (3) Theology; (4) History; (5) Geography; (6) Anthropology and Ethnology; (7) Social Sciences; (8) Sociology; (9) Political Science; (10) Law; (11) Education; (12) Music; (13) Fine Arts; (14) Language and Literature; (15) Science; (16) Agriculture; (17) Technology; (18) Military Science; (19) Naval Science; and (20) Bibliography and Library Science. A chronological list of imported collections and an index are included. [Best copy available has been provided.]