Book excerpt: Based on extensive research in several international contexts, this volume provides a nuanced assessment of the historical evolution of private security and its fluid, contested and mutually constitutive relationship with state agencies, public policing and the criminal justice system. This book provides an overview of the history of private security provision in its multiple forms including detective agencies, insurance companies, moral campaigners, employers’ associations, paramilitary organizations, self-protection and vigilantism. It also explores the historical evolution of private policing and security provision in a diverse set of temporal, national and international contexts and compares the interactions between public and private security bodies, structures, strategies and practices in different countries, cultures and settings. In doing so, the volume fills the existing gaps in historical knowledge about the emergence of private and public security organizations and provides a more robust understanding of changes in the division of responsibility for security provision, law enforcement and punishment between public and private institutions. This wide-ranging volume will be of great interest to scholars and students of history, criminology, sociology, political science, international relations, security studies, surveillance studies, policing, criminal justice and law.