Frank Schimmelfennig is Professor of European Politics and a member of the Center for Comparative and International Studies at ETH Zurich. He is also a Fellow of the Robert Schuman Centre of Advanced Studies at the European University Institute, Florence, and Chairman of the Scientific Board of Institut für Europäische Politik Berlin. His research focuses on European integration and, more specifically, integration theory, EU enlargement and Europeanization, differentiated integration, democracy promotion and democratization. His most recent book is Ever Looser Union? Differentiated European Integration (Oxford University Press, 2020, with Thomas Winzen).