Professor Jon Elster is the Robert Merton Professor OF Social Science at Columbia University. He received his Ph.D. from the University of Paris in 1972. Before coming to Columbia University, he taught at Paris, Oslo and Chicago. His publications include Ulysses and the Sirens (1979), Sour Grapes (1983), Making Sense of Marx (1985), The Cement of Society (1989), Solomonic Judgements (1989), Nuts and Bolts for the Social Sciences (1989), Local Justice (1992) and Political Psychology (1993). His research interests include the theory of rational choice, the theory of distributive justice and the history of social thought (Marx and Tocqueville).