Michael Wallerstein's untimely death in January 2006 spurred us to compile this volume of Wallerstein's writings. The support that we received in this endeavor propelled the volume forward in record time. We thank Lewis Bateman, Scott Parris, and Kimberly Twist at Cambridge University Press, as well as the editor of this series, Margaret Levi, all of whom did much to make this project a reality. We also thank the anonymous reviewers of the manuscript for their speedy and helpful comments on the volume.

Finally, we are grateful for the support we have received from the entire Wallerstein family: Michael's parents, Bob and Judy; his sisters, Nina and Amy; his wife, Liz; and his children, Jonah and Hannah. This volume is dedicated to Michael's memory, but we hope that it will also offer some degree of comfort to the living.