Criminal Law, branch of law that defines crimes and fixes punishments for them. Also included in criminal law are rules and procedures for preventing and investigating crimes and prosecuting criminals, as well as the regulations governing the constitution of courts, the conduct of trials, the organization of police forces, and the administration of penal institutions. In general, the criminal law of most modern societies classifies crimes as offences against the safety of the society; offences against the administration of justice; offences against the public welfare; offences against property; and offences threatening the lives or safety of people.
In England and Wales criminal trials are heard in dedicated courts: the magistrates’ court for less serious offences, and the Crown Court for all other offences. Reform of the law is under continuous examination by the Criminal Law Revision Committee, which reports to the Lord Chancellor (the head of the judiciary).
In the United States, criminal law has a number of unique features. In many particulars it varies from state to state, for example. Underlying most of the divergences is an identity of standpoint and tradition derived from English common law, which is the origin of nearly all US law. American criminal law also classifies a crime with respect to its gravity, such as treason, felony, and misdemeanour. These distinctions are obsolete in English law.