JAMES E. ALT is Frank G. Thomson Professor of Government and director of the Center of Basic Research in the Social Sciences at Harvard University. MARGARET LEVI is professor of political science and Harry Bridges Chair in Labor Studies, University of Washington, Seattle. She is also director of the University of Washington Center for Labor Studies. ELINOR OSTROM is codirector of the Workshop in Political Theory and Policy Analysis and the Center for the Study of Institutions, Population, and Environmental Change at Indiana University, Bloomington. She is also Arthur F. Bentley Professor of Political Science. CONTRIBUTORS: James E. Alt, Kenneth J. Arrow, Gary S. Becker, James M. Buchanan, Norman Frohlich, Barbara Geddes, Robert E. Goodin, Russell Hardin, Bryan D. Jones, Robert O. Keohane, David D. Laitin, Margaret Levi, Douglass C. North, Joe A. Oppenheimer, Elinor Ostrom, Vincent Ostrom, Ronald Rogowski, Norman Schofield, Thomas Schwartz, Reinhard Selten, Kenneth A. Shepsle, and Herbert A. Simon.