Europeanization has become a major theme within European studies in recent years, emphasizing the domestic effects of the EU on its member and applicant states. At the same time, multilevel governance has emerged as an important concept, highlighting shifts both in horizontal relations between state and society and in vertical links between actors at different territorial levels. In this state-of-the-art study, Ian Bache traces the relationship between these two key elements, considering the extent to which Europeanization advances multilevel governance within member states through the requirements of EU cohesion policy. Bache focuses especially on Britain, a member state whose political system has been increasingly characterized by multilevel governance since it became an EU member. Comparing Britain's case to that of ten other member states, the author distinguishes between the EU's effects in simple polities—in which voice, influence, and power are diffused through multiple levels and modes of governance—and in compound polities, where voice, influence, and power are more concentrated. Bringing together the conceptual tools of multilevel governance and policy networks and developing a framework for using these tools together in future research, this clearly written study will be valuable for scholars and students of EU and British politics.