This volume presents an overview of recent development, operation, and diverse applications of nano materials as chemical sensors, biosensors, and wireless sensing networks for myriads of legends driven by the ability to create significantly smaller, more sensitive, faster-responding, and less costly sensors which either negate or complement the use of cumbersome and less feasible conventional sensing system. Research and development in the nano sensor domain is driven by specific application requirements and social concerns. Nano sensors validates its eminence in varied field starting from electronics and security, aerospace and defense, healthcare, chemical materials and food technologies. This volume is a meticulous amalgamation of positive and negative aspects of nano materials to be used, electro and chemical nano biosensors, pollutant and environmental sensors. This volume discusses applications of semiconductor nano materials, a tamer nanostructures, signaling molecular switches, nano particle based optical determination of xenobiotics and pathogens as clinical diagnostic equipment, DNA sequencing and DNA based biocatalysts technology, Chemical and gas detection systems, nuclear radiation and humidity sensing system and biosynthesis of efficient, effective and low-cost nano materials. This volume will surely be a very helpful and effective guide for the upcoming researchers and students of biology, engineering and medicine to not only gain precise and prudent insight about nano sensing but also help to iron out several technological difficulties and issues regarding production and technology development of nano sensors.