ARTHUR MARWICK has been Professor of History at the Open University since 1969 and was formerly its Dean and Director of Studies in Arts. His visiting appointments include positions at the State University of New York at Buffalo, Stanford University, California, the hoover Institution and L'Ecole des Hautes Etudes en Sciences Sociales, Paris. He has published extensively, concentrating on twentieth-century social history and the impact of war. His contribution to the philosophy of history, The Nature of History, is proving its enduring worth with a third edition in 1988.