Behavioural psychology is one of the major copies taught in every introductory psychology course, yet many concepts that lie at the heart of this subject tan be confusing for students. The interests among behaviour analysts today are wide ranging as a review of the 30 Special Interst Groups (SIGs) within ABAI indicates. Such interests include everything from developmental disabilities ard autism, to cultural psychology, clinical psychology, verbal behaviour. Organizational Behaviour Management. Although operant conditioning plays the largest role in discussions of behavioural mechanisms, classical conditioning is also an important behaviour-analytic process That need not refer to mental or other internal processes.This encyclopaedia provides a novel review and integration of the empirical literature and gives clinicians and researchers a valuable new theoretical base for assesing and treating psychological disorders.