Metropolisation: the winding road toward the citification of the region

We aim to consolidate the concept of metropolisation as a lens to examine urban region integration in territories characterized by extensive urbanization. Metropolisation is defined as the process through which institutionally, functionally, and spatially fragmented urbanized regions become integrated as coherent metropolitan systems. This novel framework is captured by three notions: inversion, multiplexity, and convergence. Inversion changes the dominant perspective of cities dissolving into urban regions (the “regionalization of the city”) toward urban regions consolidating into extensive cities (the “citification of the region”). Multiplexity examines this process as a continuous interaction of intertwined spatial-functional, political-institutional, and cultural-symbolic facilitators and inhibitors of integration with overlapping effects. Convergence stresses the blurred distinctions between concepts that used to belong either to the “urban” or the “regional”. This editorial to the special issue explores the multilingual genealogy of metropolisation, discusses its ability to understand contemporary urbanization, and examines its implications for theory and policy.