Dr. Charles Lipson taught international relations at the University of Chicago, where he was the Peter B. Ritzma Professor in Political Science and the College. His research deals with international cooperation and conflict and with political aspects of the world economy. His most recent book on international relations, Reliable Partners: How Democracies Have Made a Separate Peace, explains one of the most striking features in world politics: why democracies do not fight wars against each other. (Princeton University Press, 2003). Dr. Lipson has also written extensively on international trade, debt, and investment. His book, Standing Guard: Protecting Foreign Capital in the Nineteenth and Twentieth Centuries, has been widely praised for combining politics and economics. It is concerned with the problems faced by successful corporations when they operate in difficult political environments around the world. Professor Lipson's most recent work deals with the problems of forging international cooperation after the Cold War. He is currently writing about the sources of international order in the nineteenth and twentieth centuries.