This three-volume encyclopedia provides a thorough examination of the components comprising behavior modification, behavior therapy, cognitive behavior therapy, and applied behavior analysis for both child and adult populations in a variety of settings (e.g., outpatient, institutional, classroom). Although the focus is on technical applications, entries also provide historical context to apprise readers of the parameters in which behavior therapists have worked, including research issues and strategies. Thus, entries on assessment, ethical concerns, theoretical differences, and the unique contributions of key figures in the movement (e.g., B. F. Skinner, Joseph Wolpe, Aaron T. Beck) are also included.