The rapid expansion of peacekeeping after the end of the Cold War has thrust the military into a new and unfamiliar world in which it has to develop a close relationship with civilians at all levels - strategic, tactical and operational. Operations in Cambodia, Haiti, Somalia and the former Yugoslavia, whether under UN or NATO auspices, have revealed the difficulties inherent in civil-military co-operation. This paper reviews these experiences and makes recommendations for developing a more effective civil-military relationship.