This book examines in detail the basic properties and design, including chip integration, of CMOS and bipolar VLSI devices and discusses the various factors that affect their performance. The authors begin with a thorough review of the relevant aspects of semiconductor physics, and proceed to a description of the design of CMOS and bipolar devices. The optimization of these devices for VLSI applications is also covered. The authors highlight the intricate interdependencies and subtle trade-offs between those device parameters, such as power consumption and packing density, that affect circuit performance and manufacturability. They also discuss in detail the scaling, and physical limits to the scaling, of CMOS and bipolar devices. The book contains many exercises, and can be used as a textbook for senior undergraduate or first-year graduate courses on microelectronics or VLSI devices. It will also be a valuable reference volume for practising engineers involved in research and development in the electronics industry.