Europe has pioneered regional integration, and studies on European integration have dominated the study of regionalism. Curiously, as much as the study of regionalism has long been Europe-centered, the study of European regionalism and the theories of European integration have centered on the European Union (EU), its organizational growth and performance. This literature is vast and discussed in entire handbooks on the EU (e.g. Jones et al. 2012; Jørgensen et al. 2006). By contrast, this chapter deliberately takes a regional perspective. It starts with a discussion of how “Europe” has been constructed as a civilizational and institutional region and how it has developed from being the core region of the global system to the divided region of the Cold War era to the post-1990 unified region. Rather than looking at regionalism as a process of uniform deepening and widening of the EU, the chapter conceives of European integration as the establishment of a region-wide system of differentiated integration, which extends to virtually all policy areas and countries but integrates them at different levels of centralization. Understanding European integration as differentiated region-building requires a refocusing of both theories and impact assessments of European integration
