This textbook is for courses on Mechanical Behavior of Materials taught in departments of Mechanical Engineering and Materials Science. The text includes numerous examples and problems for student practice. The book emphasizes quantitative problem solving. End of the chapter notes are included to increase students' interest. This text differs from others because the treatment of plasticity has greater emphasis on the interrelationship of the flow, effective strain and effective stress and their use in conjunction with yield criteria to solve problems. The treatment of defects is new. Schmid's law is generalized for complex stress states. Its use with strains allows for prediction of R-values for textures. Another feature is the treatment of lattice rotations and how they lead to deformation textures. The chapter on fracture mechanics includes coverage of Gurney's approach. Much of the analysis of particulate composites is new. Few texts include anything on metal forming.