HÉLÈNE COMBES is CNRS Research Fellow with the Centre de recherches politiques de la Sorbonne, Paris 1 University, France DONATELLA DELLA PORTA is Professor of Sociology in the Department of Political and Social Sciences at the European University Institute, Italy MARCO GIUGNI is Researcher at the Laboratoire de recherches sociales et politiques appliquées (resop) and teaches in the Department of Political Science at the University of Geneva, Switzerland NICOLAS HAERINGER is a doctoral researcher at the CERSO (Centre d'étude et de recherche en sociologie des organisations), Université Paris-Dauphine, France RAFFAELE MARCHETTI is Lecturer on International Relations at LUISS University and John Cabot University, Italy LORENZO MOSCA is a Postdoctoral Fellow at the European University Institute and is currently a research fellow at the Bocconi University (Milan), Italy ALESSANDRO NAI works as a teaching and research assistant in Political Science at the University of Geneva, Switzerland MARIO PIANTA is Professor of Economic Policy at the University of Urbino, Italy HERBERT REITER is Researcher at the European University Institute, Florence, Italy DIETER RUCHT is Professor of Sociology and co-director of the research group 'Civil Society, Citizenship and Political Mobilization in Europe' at the Social Science Research Center, Berlin, Germany CLARE SAUNDERS is Lecturer and RCUK Fellow in Politics and International Relations at the University of Southampton,UK ISABELLE SOMMIER is Professor at the Sorbonne, Paris, France SIMON TEUNE works at the Social Science Research Center, Berlin, Germany DUCCIO ZOLA is currently a PhD student in philosophy at the University of Rome 'La Sapienza', Italy