This chapter attempts to contribute to the consolidation of a fragmented field in search of its own intellectual history. The long time perspective reveals the intellectual richness of the field. It also makes it possible to trace the various ways in which earlier ideas about regions and region-building have influenced more recent ideas and projects. The chapter identifies four general phases in the scholarly development of the field: early regionalism, old regionalism, new regionalism, and the latest and current phase of regionalism, referred to as “comparative regionalism.” With the exception of early regionalism—which covers a vast array of ideas and traditions from different spaces and times—the three remaining intellectual discourses are described in a similar way. First, the political context and the policy content are outlined. Thereafter the analysis focuses on theoretical and conceptual issues, the research agenda and methodology.