The relationship between the European Union and its member states is complex and continually evolving. This book seeks to explore not only the nature of this relationship, but the broader implications of European integration for the ways in which politics in Europe is studied. It addresses three major questions. How has European integration affected national politics and public policies? To what extent has the existence of the EU challenged existing approaches to the study of national politics? How appropriate is it to attempt to study the EU using the analytical tools traditionally used to study nation states? The intention is to consider the impact of European integration both on the nature and the study of politics in western Europe. These questions are addressed by a group of distinguished academics from both Europe and North America. Their findings will be of great interest to all those interested in the European Union and in West European politics more generally.