Social workers in corrections must have the same general knowledge required and expected of all social workers. In addition, they must have a specialized body of knowledge that pertains to offending behavior, factors that contribute to crime, theories and models of deviance, organizational issues, the criminal justice system, and the effectiveness of various types of intervention for different types of offenders. In outlining the characteristics of these various bodies of knowledge, this article focuses first on criminology and the study of crime and deviance. It discusses various explanations of crime and deviance, including those related to biological, economic, psychological, sociological, and conflict theories. The article then addresses the effectiveness of intervention and sanctions. It discusses general theories, theoretical constructs, and techniques that have been found to be empirically effective in the treatment of offenders. One treatment approach that meets this condition is cognitive-behavioral therapy. This therapy is based in the principle that behavior can be modified through the systematic use of empirically based learning principles. This therapeutic method is a relatively short-term form of psychotherapy that is active and directive. Behavioral therapy and behavioral modification are also discussed. Behavioral therapy emphasizes counterconditioning, which refers to the interchanging of one type of response for another more acceptable response based on learning principles. Behavior modification emphasizes the use of conditions and stimuli that foster and condition positive behaviors. Other treatment techniques mentioned are psychoanalysis, logotherapy, system theory, and reality therapy. 35 references