Now in a completely revised and expanded second edition, this authoritative handbook reviews the breadth of current knowledge on the psychological processes that underlie social behavior. Leading investigators identify core principles that have emerged from the study of biological systems, social cognition, goals and strivings, interpersonal interactions, and group and cultural dynamics. State-of-the-science theories, methods, and findings are explained, and important directions for future research are highlighted. More than an update, this edition is virtually a new book. Many more chapters are included, and significant advances in social cognitive neuroscience, motivational psychology, and other areas are incorporated throughout. A new section addresses implications for applied domains, such as clinical psychology, health, and consumer behavior.