David Johnston is the Director of Undergraduate Studies in the Political Science Department at Columbia University, where he is also Professor of Political Science. Professor Johnston received his PhD from Princeton in 1981, after which he taught at Yale University before coming to Columbia. He has served as Chair of the International Conference for the Study of Political Thought, as President of the New York State Political Science Association, and as Chair and Director of the Society of Fellows in the Humanities at Columbia. His publications include The Idea of a Liberal Theory, The Rhetoric of Leviathan: Thomas Hobbes and the Politics of Cultural Transformation, and, as editor, Equality and (with Richard Flathman) Leviathan: A Norton Critical Edition. He has recently completed A Brief History of Justice. His research interests include theories of justice, the liberal tradition of political theory, and the history of political thought. He is currently studying the relationship between justice and reciprocity.