While most of us now live in places called cities, our experience of city or urban life varies profoundly according to how wealthy we are, our age, gender, class or ethnic background, and whether we live alone or as part of more extensive family and kinship networks. Of course these factors also shape our experience of life in other non- city settings, but the urban dimension is significant to the extent that Louis Wirth (1938) spoke of ‘urbanism as a way of life’. However we define them, our cities have been growing because increasing numbers of people choose to live in them: they choose to move to them from other places and they choose to remain in them (Glaeser, 2011). This is not of course to suggest that these choices are always freely made or free from significant constraints, but cities continue to offer the prospect of a better life than other places and while the precise nature of this prospect varies over time and between places, it usually involves a series of material benefits that do not exist or are much less prevalent elsewhere. As Saunders observes in his book, Arrival City (2010), migrants from rural areas in developing and fast-growing countries are attracted to cities because of the economic opportunities they offer and by material benefits such as reticulated water, reliable power supply, public transport, decent housing and maybe also by more ephemeral and cultural attractions. The fact that for many recent migrants to the rapidly growing cities of the world these opportunities and benefits are not as accessible as they had hoped does not typically deter subsequent migrants or prompt many migrants to leave cities in general, even though they might move to another city.