Mercenaries have been employed as auxiliaries since early times, but in the post-1945 world they have operated, almost exclusively, in weak Third World countries. From Columbia to the Congo, Angola to Papua New Guinea, Cambodia to Nicaragua, they have appeared: training the drug cartel armies, assisting rebellions or civil wars, acting as the agents of the major powers. In the Congo crisis (1960-1965) they earned an especially unsavory reputation...