Modern interpersonal psychology is now at a point where recent advances need to be organized so that researchers, practitioners, and students can understand what is new, different, and state-of-the art. This field-defining volume examines the history of interpersonal psychology and explores influential theories of normal-abnormal behaviors, widely-used assessment measures, recent methodological advances, and current interpersonal strategies for changing problematic behaviors. Featuring original contributions from field luminaries including Aaron Pincus, John Clarkin, David Buss, Louis Castonguay, and Theodore Millon, this cutting-edge volume will appeal to academicians, professionals, and students interested in the study of normal and abnormal interpersonal behavior.