The growing applicati0ns of Very Large Scale Integration in all the fields of electronics, particularly consumer and professional electronics, demand the working engineers/professionals to know more about VLSI. With this objective in view, the Indian Society for Technical Education (ISTE), which is a non-profit organization, requested the authors to prepare Learning Materials on VLSI for the working professionals. The material in this Book is prepared by emphasizing the basics of CMOS (Complementary Metal Oxide Semiconductors) Transistors, their characterization, process, Logic circuits, subsystems, and the design of systems using Computer Aided Design (CAD). This material gives the overview of VLSI, particularly the digital circuits and systems. The topics for this book are based on many text books on VLSI and from materials given in various websites. We thank all the authors and publishers of the books and websites.