This book concentrates upon the mathematical theory of plasticity and fracture as opposed to the physical theory of these fields, and is presented in the thermomechanical framework. It follows the macroscopic, phenomenological approach which proposes equations abstracted from generally accepted experimental facts, studies the adequacy of the consequences drawn from these equations to those facts and then provides useful tools for designers and engineers. The material is drawn from the author’s graduate course in Europe and the United States and may be used to form the basis for similar graduate courses on plasticity and fracture. Many worked examples are presented and each chapter concludes with problems for students. The book will thus undoubtedly establish itself as a core text for both students and researchers.