This book is the first of a new, seven volume series which aims to provide a comprehensive description of basic methods and technologies related to CAD for VLSI. The series includes up-to-date results and latest developments, with a good balance between theoretical and practical aspects of VLSI design. In this volume emphasis is placed on the basics of modeling, the opening chapters being devoted to fundamental process and device modeling. The following chapters cover different aspects of device modeling and also bridge to process simulation on the one side, and circuit simulation on the other. A systems approach to physical modeling, spanning the whole range of topics covered, is also dealt with. Recent conferences on the subject have signalled that physical modeling combined with technology, device and circuit optimization, will undoubtedly become a major trend in the future.