This book deals with the analysis and design of analog integrated circuits that form the basis of present-day communication systems. The material is intended to be a textbook for class use but should also be a valuable source of information for a practicing engineer. Both bipolar and MOS transistor circuits are analyzed and many numerical examples are used to illustrate the analysis and design techniques developed in this book. A set of problems is presented at the end of the book which covers the subject matter of the whole book. The book has originated out of a senior-level course on nonlinear, analog integrated circuits at the University of California at Berkeley. The material contained in this book has been taught by the first author for several years and the book has been class tested for six semesters. This along with feedback from the students is reflected in the organization and writing of the text. We expect that the students have had an introductory course in analog circuits so that they are familiar with some of the basic analysis techniques and also with the operating principles of the various semiconductor devices. Several important, basic circuits and concepts are reviewed as the subject matter is developed.