World cities face the twin challenges of metropolitan socioeconomic restructuring and spatial decentralization. New York's global financial and managerial roles, coupled with deindustrialization and corporate relocation, have polarized social areas. Census data from 1970 and 1990 for the New York metropolitan area indicate demographic and employment shifts, social and ethnic divisions, concentration of wealth and poverty, and exurban growth pressures. The evolution of greater New York from a monocentric to a polycentric metropolis, divided into semiautonomous and competing realms, suggests a reordering of urban space that may become a pattern in other world cities. Key words: corporate location, deindustrialization, economic restructuring, New York City, world cities. The emergence of giant cities brings an expanded scale, a heightened interdependence, and a pressing urgency to global problems. Twenty-two metropolises are projected to exceed 10 million inhabitants each by 2000. As human settlements reach such unprecedented size, the sprawling urban regions face the paradox of local fragmentation in the midst of global integration. With worldwide transactions synchronized by the logic of a unified market mechanism, urban centers react to the oscillations of distant economies and strain the resources of remote hinterlands. International economic integration and technological innovation also allow corporate operations to disperse from central locations, which makes cities vulnerable to sudden economic upheavals. Leading metropolises therefore compete nationally and internationally to attract profitable enterprises with promises of financial incentives and subsidies, low-cost labor, and modern infrastructures. The resulting decentralization of employment heightens inequitable spatial patterns of income distribution, social welfare, and public expenditure.