The first book dedicated to the sociology of privatized security, this collection studies the important global trend of shifting security from public to private hands and the associated rise of Private Military and Security Companies (PMSCs) and their contractors. The volume first explores the trend itself, making important historical and theoretical revisions to the existing social science of private security. These chapters discuss why rulers buy, rent and create private militaries, why mercenaries have become private patriots, and why the legitimacy of military missions is undermined by the use of contractors. The next section challenges the idea that states have a monopoly on legitimate violence and questions our legal and economic assumptions about private security. The collection concludes with a discussion of the contractors themselves, focusing on gender, race, ethnicity, and other demographic factors. Featuring a mix of qualitative and quantitative methods and a range of theoretical and methodological innovations, this book will inspire sociologists to examine, with fresh eyes, the behind-the-scenes tension between the high drama of war and conflict and the mundane realities of privatized security contractors and their everyday lives.