This article explores the history and growth of mercenary groups, then concludes with some thoughts on the future of such groups. "It is a very old practice for rulers to fight some or all of their wars by hiring foreigners, militarily skilled groups and individuals who have no special ideological stake in the conflict at hand. Loosely speaking, these hired soldiers are grouped together as 'mercenaries.' At the dawn of the 21st century, when various entities (states, corporations, political movements, etc.) find themselves in need of military or large-scale security services, hiring mercenaries is an obvious recourse. When even major states are reducing their armed forces and showing less interest in foreign military adventures because of pinched economic circumstances and a changed political environment, smaller states may be doubly motivated to go the presumably cheaper mercenary route. During the 1990s a number of corporations termed 'international security firms' or 'private military companies.' [...]. For purposes of this discussion, we will use the ordinary language definition of a mercenary: individuals or organizations who sell their military skills outside their country of origin and as an entrepreneur rather than as a member of a recognized national military force. The particular emphasis here is on those groups organized as corporations that provide such services."
U.S. Army War College, Parameters: http://www.carlisle.army.mil/usawc/parameters/
Parameters: United States Army War College Quarterly (Summer 1999), v.29 no.2, p.103-116