The popularization of ‘World City’ as an analytical concept dates to 1966. Taking up a term introduced fifty years earlier by Patrick Geddes, Peter Hall's now classic description ofThe World Citiesexplored the evolution of a handful of key urban areas from national into global roles and functions. The original emphasis on size and comprehensive economic functins has since been extended by the argument that a distinct class of global cities are a characteristic product of the technologies and economy of the late twentieth century. As well, such cities are thought to embrace common spatial forms that respond to a specific balance of centralizing and decentralizing tendencies in the location of commercial, financial, and manufacturing industries.