This work is a revision and extension of the author's 1995 "Sourcebook of Control Systems Engineering". Because of the extensions and other modifications, it has been re-titled, and is intended to be for its prime audience - advanced undergraduate students, beginning graduate students, and practicing engineers needing an understandable review of the field or recent developments which may prove useful. New in this edition are two chapters on aspects of nonlinear systems. In the first of these, selected material for nonlinear systems is concentrated on four aspects: showing the value of certain linear controllers, arguing the suitability of algebraic linearization, reviewing the semi-classical methods of harmonic balance, and introducing the nonlinear change of variable technique known as feedback linearization. In the second new chapter, the topic of variable structure control, often with sliding mode, is introduced. A third chapter introduces discrete event systems, including several approaches to their analysis. The chapters on robust control and intelligent control have been extensively revised. Modest revisions and extensions have also been made to other chapters, often to incorporate extensions to nonlinear systems. Many references have been updated to more recent books, although old standards are still cited. Also, some of the advances in computer and communications technology are reflected.