However we choose to define the word 'urbanisation', and whether we are inclined to regard it as referring to a primarily economic, demographic or social-behavioural process, there can be little doubting the fact that it signifies one of the most problematical processes confronting mankind in the last two decades of the twentieth century and beyond. It is hardly surprising, therefore, that during the postwar period, a vast literature has developed within the social sciences which specifically seeks to examine the manifold historical, contemporary and prospective aspects of the global trend of urbanisation. This corpus of writing obviously reflects the simple truism that urbanisation involves fundamental shifts and changes in the whole fabric of nations, regions and continents, not least in their social, economic and demographic structuring. Further, it is hard to refute the assertion that along with efforts to alleviate global poverty and hunger, to promote greater equality of opportunity by careful social development, and to enhance world peace and individual security, the tackling of problems associated with rapid urban development will test the ingenuity of mankind to the utmost, and may yet determine the capacity for sustained global development in the future.