The threefold structure of this book describes the history of the police, the sociology of policing, and the law and politics of the police. The introduction of this book distinguishes between who the police are and what policing is in the United Kingdom. The term "police" refers to a particular kind of social institution, while "policing" implies a set of processes with specific social functions. The idea of policing is an aspect of the more general concept of social control. Part 1 provides interpretations of police history, the orthodox story of policing, the revisionist account, and a critique and synthesis. The establishment of the police was a painful process, which produced resistance and hostility. In the late 18th and early 19th centuries the police idea was fiercely contested. Part 1 details the rise and fall of police legitimacy from 1856 to 1991. This includes the depoliticization of the police from 1856 to 1959, and the politicization of the police since 1959. Part 2 considers the knowledge gained by studies of police culture and work. An understanding of how police officers see the social world and their role in it is important to an analysis of what they do. The core characteristics of cop culture, social research and police practice, and the media presentation of policing are described. Part 3 describes police powers and accountability. The last two decades have seen profound changes in the legal and constitutional status of the police. Their powers and accountability have been transformed by a set of overt changes in statute and case law, and by covert changes in policy and practice. The new millenium of policing, the cycles of reform, the British New Labour Government and policing, and the limits of police reform and policing are discussed. Appendix, bibliography, index