For more than twenty years, this indispensable resource has been the reference of choice for psychologists, researchers, teachers, and students who need up-to-date and comprehensive information in the fields of psychology and behavioral science. Updated and expanded to include much new material, this paperback is the only reference source that effectively blends psychology and behavioral science. This edition features over 1,200 entries, sixty percent of which are substantially revised or altogether new; contributions from over seven hundred experts from around the world; a bibliography of over 10,000 citations.