David Schmidtz is Professor of Philosophy, joint Professor of Economics, and Director of the Program of Philosophy of Freedom at the University of Arizona. He is author of the newly released A Brief History of Liberty (with Jason Brennan),  Elements of Justice (Cambridge, 2006), Rational Choice and Moral Agency (Princeton, 1995), The Limits of Government: An Essay on the Public Goods Argument (Westview, 1991), and co-author of Social Welfare and Individual Responsibility (Cambridge, 1998) with Robert Goodin. His academic articles have appeared in journals such as the Journal of Philosophy, Ethics, and Political Theory, and many have been reprinted in textbooks and other languages. He has edited a volume on Robert Nozick (Cambridge, 2002) and co-edited Environmental Ethics: What Really Matters, What Really Works (Oxford, 2001) with Elizabeth Willott. His current book projects are The Purpose of Moral Theory and A Brief History of Liberty (with Jason Brennan). He has lectured at over fifty universities, in sixteen countries, on six continents.