The legal definition of crime reflects the central philosophy of the American system of law--that an act, or the omission of an act, must be committed and that persons cannot be punished for thoughts. The concept of criminal intent is also a part of the legal definition. The definition of crime most acceptable to sociologists suggests that an act is a crime only when it is in violation of criminal law. Within the context of drug use, one must necessarily accept crime's legal definition to measure and process the crime. Categorizing behaviors that are against the law is one way to arrive at a definition of crime, but one that involves difficulties posed by differences in local laws which may or may not consider the same act a crime and by differences in local definitions of the same act. Since drug-related crimes are generally economic in nature, their classification falls into both Uniform Crime Report Part I and Part II categories. A more functional classification scheme for drug-related crimes includes grouping them into violent personal crime, property crime, and public order crime. A methodological debate regarding the categorizing of crimes has centered on the use of descriptive versus quantitative typologies in describing offenses and offenders. Agreement has been reached that any organizational typology should include the legal category of offense, the frequency with which criminal acts are committed, the social cost of a crime in terms of the extent of property loss and violence, and the perceived intensity of the criminal act. Other focuses of the typology debate include regarding and defining the crime from the subject's or criminal's perspective as well as from those of the victim and the police. A total of 52 references are included. For the full drug use and crime report, see NCJ 40293.