Regionalism – that is, the tendency for states to form regional groupings – has attracted considerable attention as a major force for global change. The proliferation and diversity of the regional integration regimes across the world has spawned major debates, focusing on the various designs, motives and modalities of participation and varying rates of integration. The ‘new regionalism’, mainly involving non-Western and often non- democratic states at various levels of economic development, greatly enriched the knowledge of regional integration in becoming the focus of the so-called ‘second wave’ of literature on regionalism. Research on the design and effects of regional institutions has benefitted considerably from the increased number of case studies. Scholars of international law and international relations have examined the diversity of regional integration regimes with particular reference to the mechanisms of coordination they use and the extent to which they resort to binding, legalized commitments in structuring cooperation. However, developments in the communist bloc were treated as a distinct phenomenon and were not fully embraced by the literature on new regionalism. The East-Central European states rushed to join the European Union (EU) and NATO, even before their accessions were duly absorbed into the fold of European studies with their distinct analytical perspectives associated with the ‘old’ regionalism. In contrast, the post-Soviet states featured only occasionally in comparative studies of regionalism.