Cropsey was a student of Leo Strauss, who inspired him to move from his original academic field—economic thought—to a much more theoretical approach to political thought. Since then, Cropsey had focused on Plato and the "esoteric", interstitial philosophical aspects of the theories developed by such thinkers as Adam Smith and Karl Marx.
Joseph Cropsey (ed.), Ancients and Moderns: Essays on the Tradition of Political Philosophy in Honor of Leo Strauss, New York, Basic Books, 1964 ISBN0-465-00326-5
Joseph Cropsey, Political Philosophy and the Issues of Politics, Chicago & London, University of Chicago Press, 1977 ISBN0-226-12123-2
Joseph Cropsey, Plato's World: Man's Place in the Cosmos (1995), Chicago & London, University of Chicago Press, 1997 ISBN0-226-12122-4
Joseph Cropsey, Polity and Economy: An Interpretation of the Principles of Adam Smith (With Further Thoughts on the Principles of Adam Smith), Chicago, St. Augustine's Press, 2001 (Revised Edition) ISBN1-58731-625-0
Thomas Hobbes (edited by Joseph Cropsey), A Dialogue between a Philosopher and a Student of the Common Laws of England (written between 1668 and 1675), Chicago & London, University of Chicago Press, 1997 ISBN0-226-34541-6
Leo Strauss, Joseph Cropsey (eds.), History of Political Philosophy (First Edition: 1963), Chicago & London, University of Chicago Press, 1987 ISBN0-226-77710-3
Joseph Cropsey, On Humanity's Intensive Introspection, South Bend, IN, St. Augustine's Press, 2012 ISBN978-1-58731-611-1