The first text that specifically links both international and internal migration with development at a global level. Taking an innovative approach, the world is divided into a series of functionally integrated development zones which are identified, not simply on the basis of their level of development, but also through their spatial patterns and historical experience of migration. It goes on to stress the importance of migration in discussing regional, rather than simply country, differences. These variations in mobility are placed within the context of a global hierarchy, although regional, national and local cultural and social conditions are certainly not ignored in this wide-ranging work.