Far from displaying a uniform pattern of integration, the European Union varies significantly across policy areas, institutional development and individual countries. Why do some policies such as the Single Market attract non-EU member states, while some member states choose to opt out of other EU policies? In answering these questions, this innovative new text provides a state-of-the-art introduction to the study of European integration. The authors introduce the most important theories of European integration and apply these to the trajectories of key EU policy areas - including the single market, monetary policy, foreign and security policy, and justice and home affairs. Arguing that no single theory offers a completely convincing explanation of integration and differentiation in the EU, the authors put forward a new analytical perspective for describing and explaining the institutions and policies of the EU and their development over time. Written by a team of prominent scholars in the field, this thought-provoking book provides a new synthesis of integration theory and an original way of thinking about what the EU is and how it works.

Dirk Leuffen is Professor of International Politics at the Department of Politics and Public Administration, University of Konstanz, Germany. Berthold Rittberger is Professor of International Relations at the Geschwister-Scholl-Institute of Political Science, University of Munich, Germany. Frank Schimmelfennig is Professor of European Politics at ETH Zurich, Center for Comparative and International Studies, Switzerland.