The phenomenological, mechanistic and micro-structural aspects of the mechanical properties of materials are developed, with particular emphasis on the similarities and differences among various material systems including metals, ceramics and polymers. Phenomenological aspects of the three-dimensional characteristics of stress and strain, various yield criteria, elastic behavior, viscoelastic behavior, plastic behavior, statistical aspects of brittle fracture and fracture mechanics are presented. Mechanistic and micro-structural topics include edge and screw
dislocation behavior, slip systems, critical resolved shear stress, dislocation multiplication and interactions, barriers to motion, polymer chain conformation and entropy.