This book deals with the mechanical behaviour of materials and is concerned with the most up-to-date coverage of fracture behaviour of materials. It is intended for the course in material mechanical behaviour taught at the advanced undergraduate level; it is also suitable for an introductory graduate course. Fundamental concepts and principles of mechanical behaviour of materials are defined and the similarities and differences in the mechanical response of the several materials classes (ceramics, composites, metals, and polymers) are discussed.