A popular and comprehensive guide introducing readers to the agencies of the Criminal Justice System in England and Wales. Providing basic information about the various agencies of the criminal justice system, the text also outlines the legal responsibilities and tasks held by the agencies and the contextual constraints which influence them. The legislation, history and organisational forms of the criminal justice agencies are also described, together with insights into the principles of criminal law and its procedure, and empirical studies of how these laws are implemented on a day-to-day basis.