Since the early 1990s there has been exponential growth in the private security industry as concerns about safety and risk have become increasing preoccupations in the western world. This book meets the need for a concise and up-to-date account of private policing, situating it within the context of the debates on policing more generally and the changing relationship between public and private policing. This book examines the origins of private policing, the growing literature that has sought to explain its growth, and ways in which it has been defined and classified. These include the commercial security industry, policing functions exercised by the armed forces, local authorities, state departments and by voluntary policing bodies. The increasingly important issue of patrol by private policing bodies provides the focus for an important case study, exploring the implications of the exercise of patrol powers and functions by neighbourhood wardens, patrolling security officers and others.