Economics of agglomeration

We address the fundamental question arising in geographical economics: why do economic activities agglomerate in a small number of places? The main reasons for the formation of economic clusters involving firms and/or households are analyzed: (i) externalities under perfect competition; (ii) increasing returns under monopolistic competition; and (iii) spatial competition under strategic interaction. We review what has been accomplished in these three domains and identify a few general principles governing the organization of economic space. A few alternative, new approaches are also proposed. (C) 1996 Academic Press, Inc.