This book introduces key concepts for systematically controlling engineering systems that possess interacting phenomena occurring at widely different speeds. The aim is to present the reader with control techniques that extend the benefits of model reduction of singular perturbation theory to a larger class of nonlinear dynamical systems. New results and relevant background are presented through insightful examples that cover a wide range of applications from different branches of engineering. This book is unique because it:* Presents a new perspective on existing control methods and thus broadens their application to a larger class of nonlinear dynamical systems.* Discusses general rather than problem-specific developments to certain applications or disciplines in order to provide control engineers with useful analytical tools. * Addresses new control problems using singular perturbation methods, including closed-form results for control of nonminimum.