In the 1960's, psychologists were often seen as a part of the treatment team in corrections because the prevailing view was that criminal behavior was psychopathological. In the 1980's, psychologists in corrections have more diverse roles and carry out several types of interventions. They screen and classify newly received offenders; they provide treatment-oriented services; they act as mental health practitioners; they train and consult with prison staff; and they plan, develop, and evaluate corrections programs. Additionally, they must be aware of how certain legal issues such as prison crowding; assessment and classification; a provision of mental health services; and vocation, educational, and life skills training needs impact on their work. Their professional knowledge should be used to better define the scope and rationale of psychological activity in prison settings. Corrections psychologists must stay abreast of research developments and argue for the application of well-grounded principles in corrections. They can develop behavioral approaches to community-based corrections treatment. 91 references.