C.R. MITCHELL was Professor of International Relations at the City University, London, before accepting a chair at George Mason University, Virginia. He has written extensively about the theory and practice of mediation, including The Structure of International Conflict (Macmillan 1981) and Peacemaking and the Consultant's Role (Gower Press 1981). He is a member of the Conflict Research Society and the Centre for the Analysis of Conflict.K. WEBB lectures in International Relations at University of Kent. His research and teaching interests are in the epistemology and methodology of social science and in political conflict, particularly with respect to communal and international violence and their management. He is secretary of the Conflict Research Society and a member of the Centre for the Analysis of Conflict.