The second edition of this textbook, popular among students and faculty alike, investigates the various causes of thermodynamic instability in metallic microstructures. It examines current experimental and theoretical understanding of the kinetics behind structural change in metals. The entire text has been updated in this new edition, including a completely new chapter on highly metastable alloys. A comprehensive and well-illustrated text, accompanied by ample references, this volume will allow final year undergraduates, graduate students and research workers to investigate in detail the stability of microstructure in metallic systems.