Mercenaries have been active in battle from the beginning of military history and, as private armies and military support firms, they are a major component of warfare today. Security, military advice, training, logistics support, policing, technological expertise, intelligence, transportation—all are outsourced to a greater or lesser degree in the U.S. military. However, privatization is not a uniquely American phenomenon. Countries as diverse as Saudi Arabia and Australia rely on privatization in one form or another. Historically, heads of state, politicians, and other administrators have justified use of mercenaries on the basis of their effectiveness, and cost-savings. These reasons and others continue to serve as rationales for use of private military companies in military strategy. Mercenaries: A Guide to Private Armies and Private Military Companies provides a comprehensive survey and guide to mercenary forces, entrepreneurs, and corporations active on the international military scene today, including a concise history of mercenaries and private armies on land, sea, and in the air. Narrative chapters are amply supplemented by sidebars including biographies of major figures, key statistics, historical and current documents, contracts, and legislation on private armies and outsourced military services. Each chapter includes a bibliography of books, journal articles, and web sites, and a general bibliography concludes the entire work.