The application of the 111-V compound semiconductors to device fabrica­ tion has grown considerably in the last few years. This process has been stimulated, in part, by the advancement in the understanding of the interface physics and chemistry of the III-V's. The literature on this subject is spread over the last 15 years and appears in many journals and conference proceedings. Understanding this literature requires consider­ able effort by the seasoned researcher, and even more for those starting out in the field or by engineers and scientists who wish to apply this knowledge to the fabrication of devices. The purpose of this book is to bring together much of the fundamental and practical knowledge on the physics and chemistry of the 111-V compounds with metals and dielectrics. The authors of this book have endeavored to provide concise overviews of these areas with many tales and graphs which comrade and summarize the literature. In this way, the book serves as both an insightful treatise on III-V interfaces and a handy reference to the literature. The selection of authors was mandated by the desire to include both fundamental and practical approaches, covering device and material aspects of the interfaces. All of the authors are recognized experts on III-V interfaces and each has worked for many years in his subject area. This experience is projected in the breadth of understanding in each chapter.