Many people and organizations have contributed generously as I pursued this project. I am very grateful for grants received from the George Washington University, the National Endowment for the Humanities, and the Woodrow Wilson Foundation. I would also like to thank in particular the Political Science Department at George Washington University for giving me vital support in the completion of this book. As a student of political theory, I had the great fortune to study with four thinkers whose passion for questions of politics and theory has been a continual inspiration: Jon Elster, Russell Hardin, and Stephen Holmes at the University of Chicago, and Sheldon Wolin at Princeton. Though pursued in remarkably different ways, their work testifies to the importance of ideas engaged with the world. Their hard-headedness, wit and care for humanity impressed me years ago, and still do. I thank them for reading various incarnations and portions of this book, and for showing faith in my work at critical points over the years.