Donatella Della Porta is professor of sociology in the Department of Political and Social Sciences at the European University Institute, where she teaches courses on political sociology, transformations in democracy, social movements and civil society as well as qualitative methods and research designs. She has received a Diplome d'Etudes Approfondies at the Ecole des Hautes Etudes en Sciences Sociales of Paris and a Ph.D in political and social sciences at the European University Institute in Florence. In 1990 she received a Career Development Award of the H.F. Guggenheim Foundation in 1997 a Stipendium of the Alexander von Humboldt Stiftung. She has conducted research, among others, at Cornell University, Ithaca N.Y, and at the Wissenschaftszentrum Berlin für Sozialforschung. Her main research interests concern social movements, political violence, terrorism, corruption, police and policies of public order. Manuela Caiani works for the VETO project on "Processes of Radicalisation and Violent Political Activism", focussing on right wing extremism in several European countries (Germany, Italy) and the USA. She works in the Department of Political and Social Sciences at the European University Institute as a research assistant. She has received a Ph.D in political and social sciences at the University of Florence in 2006 with a thesis on "The Public Discourse on Europe: An empirical research on the Italian case". In 2005, she received a funding award from the Italian CNR (Centro Nazionale della Ricerca), for a research project on "Cultural Identity, multiculturalism and European Integration" in 2007 she worked for the European Commission, for the elaboration of a literature review on the subject of violent radicalisation (contract n. JLSD 1/2006/12/02). Her main research interests concern social movements, Europeanization, political violence and right wing extremism, social capital.