An interdisciplinary approach to explaining criminal behavior integrates the levels of analysis. Genetics is discussed as it pertains to the development of the brain and learning of behavioral systems. The brain is discussed as it relates to learning, violence and aggression, sexual behaviors, pleasure and pain, mental illness, and cultural adaptations to the environment. Learning theory is discussed as it relates to genetics, the brain, cultural adaptation, violence and aggression, sexual behavior, mental illness, and antisocial behaviors. Social and cultural variables are addressed as they influence and are influenced by genetics, the brain, learning processes, and personality development. An interdisciplinary theory of criminal behavior views each person as a unique product of particular biological, psychological, and sociological conditions and interactions. Criminal behavior, therefore, cannot be adequately explained by the study of groups on the basis of aggregate data. Each person has a different genetic system, a different brain, a different pattern of learned responses, and a different set of environmental interactions. 65 references.