related hypothesis for research is that the economic fortunes of these cities become increasingly disconnected from their broader hinterlands or even their na- tional economies. We can see here the formation, at least incipient, of transnational urban systems. To a large extent major business centers in the world today draw their importance from these transnational networks. There is no such thing as a single global city—and in this sense there is a sharp contrast with the erstwhile capitals of empires.