Ever since the French Revolution and the rise of the rise of national armies, the mercenary has been viewed as a maligned and marginalized actor in international relations. The Mercenary challenges this view, suggesting instead that while delegated to the periphery of Great Power politics, the mercenary remained a coercive instrument of state power who was willing to discretely promote the client's foreign policy when called upon to do so. Never has this been more evident than today. This book offers fresh insight into the future of the mercenary as an instrument of state coercion and explains why there is a mercenary renaissance in the 21st century. The start of the 21st century has seen renewed interest in the mercenary from across the political spectrum. The growing reliance by the US, Russia, and China on military and security contractors suggests that the mercenary remains a key player in International Politics, now emerging from the shadows to help expand state influence on the world stage by serving as an important actor in the conduct of conflict and the winning of small wars. Far from being marginalized, the future of the mercenary is set to be increasingly active.