This book is about integrated circuit design and its fundamentals in the silicon industry. It is not intended as a design manual, but as a background to designing with the aid of CAD (computer aided design) tools. Recently application-specific integrated circuits have become key components in electronic products of all types and this book takes the view that an educated engineer should understand at least the fundamentals of circuit and fabrication technologies that have an impact on design and underlie all design decisions. The author attempts to fit integrated circuit design into a framework based on developments in silicon technology and uses this as an opportunity for bringing together interests in semiconductors, digital and analogue circuits and systems. Although intended as an introductory guide to this subject, the book does assume a basic knowledge of the background of digital and circuit electronics such as most students acquire in the first year of a degree or higher certificate course. The fundamentals of MOS circuits are discussed and this discussion can be regarded as background for semi-custom or the basis of full-custom design. The early chapters are on IC device structures and how they are made on silicon. The core of the book describes the essential steps in both semi-custom and full-custom design and the use and features of the CAD tools required to turn a chip specification into a verified, testable circuit on silicon. Emphasis is placed on digital CMOS circuits and their design which are most likely to be met in practice, but the book also includes an introduction to analogue CMOS design for mixed analogue - digital circuits and a chapter on the background of bipolar circuits.