This is the first book to describe thoroughly the many facets of doping in compound semiconductors. Equal emphasis is given to the fundamental materials physics and to the technological aspects of doping. The author describes in detail all the various techniques, including doping during epitaxial growth, doping by implantation, and doping by diffusion. The key characteristics of all dopants that have been employed in III-V semiconductors are discussed. In addition, general characteristics of dopants are analyzed, including the electrical activity, saturation, amphotericity, auto-compensation and maximum attainable dopant concentration. The timely topic of highly doped semiconductors is discussed as well. Technologically important deep levels are summarized. The properties of deep levels are presented phenomenologically. The final chapter is dedicated to the experimental characterization of impurities.