David S. Meyer is Professor of Sociology, Political Science, and Planning, Policy, and Design, at the University of California, Irvine. His general areas of interest include social movements, political sociology, and public policy, and he is most directly concerned with the relationships between social movements and institutional politics. He is author of many academic articles, and author or coeditor of 8 books; he blogs at Politicsoutdoors.com. Sidney Tarrow (PhD, Berkeley, 1965) is the Emeritus Maxwell M. Upson Professor of Government at Cornell University and an Adjunct Professor at the Cornell Law School. Tarrow has his BA from Syracuse, his MA from Columbia, and his PhD from Berkeley. A fellow of the American Academy of Arts and Sciences, Tarrow has served as Program co-Chair of the American Political Science Association Annual Meeting and as President of the APSA Section on Comparative Politics. Tarrow has been visiting professor at the Institut d'Etudes Politiques, the Central European University, the European University Institute, and the University of Trento.