The document summarizes several theories of criminal behavior, beginning with the Classical school in the 18th century. The Classical school believed criminal behavior was a result of free will and could be deterred through proportional punishment. Notable classical theorists included Cesare Beccaria and Jeremy Bentham. Later critiques found the Classical school ignored individual differences and mental state. Neo-classical theory accounted for those lacking responsibility. Sociological theories emphasized social and environmental influences on crime.