Karl-Dieter Opp is Professor Emeritus at the University of Leipzig (Germany), and Affiliate Professor at the University of Washington (Seattle). His areas of interest include crime and deviant behavior, collective action, political participation and protest, social norms and institutions, rational choice theory, and the philosophy of the social sciences. His most recent English book, also published with Routledge, is Theories of Political Protest and Social Movements. A Multidisciplinary Introduction, Critique and Synthesis (2009).