Private military and security companies (PMSUs) like Blackwater (now Xe Services, now Academi) have increasingly participated in military operations for over twenty years. Such companies operate all over the world. The range of clients is correspondingly wide: in addition to states, individual armed groups, private companies, the United Nations and other international organizations, non-governmental organizations and the International Committee of the Red Cross also use the services of PMSU. The military services provided by private companies in such operations range...