Narrow gap semiconductors obey the general rules of semiconductor science, but often exhibit extreme features of these rules because of the same properties that produce their narrow gaps. Consequently these materials provide sensitive tests of theory, and the opportunity for the design of innovative devices. Narrow gap semiconductors are the most important materials for the preparation of advanced modern infrared systems. Device Physics of Narrow Gap Semiconductors, a forthcoming second book, offers descriptions of the materials science and device physics of these unique materials. Topics covered include impurities and defects, recombination mechanisms, surface and interface properties, and the properties of low dimensional systems for infrared applications. This book will help readers to understand not only semiconductor physics and materials science, but also how they relate to advanced opto-electronic devices. The final chapter describes the device physics of photoconductive detectors, photovoltaic infrared detectors, super lattices and quantum wells, infrared lasers, and single photon infrared detectors.