The main aim of this thesis has consisted in shedding new light on the processes of construction and materialization of regions in the post-Cold War era. Challenging the widespread asumption that regions emerge and evolve in a spontaneous and unintentional fashion, this work proves that regions are social constructs that result from perpetual, deliberate and contested processes of social engineering and that have tangible consequences for their constituents. Through the region-building framework, it brings the promising region-building approach a step further by offring a replicable methodology and by applying it to the study of the Baltic Sea area between 1989 and 2004. By analyzing the nature and interests of its builders, the historical context in which they have operated, the ways they have sought to institutionalize their imagined construct, and their influence on social spatial imaginaries and practices, it reveals the existence of a post-modern approach to space and governance