The Adelphi Papers are a well-established series which the IISS has been publishing since 1961. Written by experts from around the world, providing in-depth analysis of important current issues and problems of international security concern. Since the end of the Cold War there has been a marked increase in attention paid to multinational military forces, for example the restructuring of NATO or the UN's involvement in peacekeeping operations. The problems of bringing together military forces from disparate nations range from the practical to the political and cultural. This paper highlights the problems of multinational formations and indicates the sorts of measures required for them to become effective policy instruments.