Variable structure systems (or sliding mode control systems) are nonlinear automatic control systems whose structures are deliberately allowed to change, so that robust performance is obtained. This allows the design of high performance control systems that can be reliably and easily implemented at low cost. This book is unique in that it aims to fulfil the definite need for an accessible book on variable structure systems and also provides the very latest results in research on this topic. Divided into three parts - basics of sliding mode control, new trends in sliding mode control, and applications of sliding mode control - the book contains many numerical design examples, so that the readers can quickly understand the design methodologies and their applications to practical problems.