In ‘urban studies’, a varied area of research that crosses over many disciplines, two contemporary areas of focus that attract much attention are ‘southern urbanism’; and comparison of cities. The first of these suggests that cities in the ‘global south’ are distinctly different from those of the ‘global north’ and require new concepts and theories to describe and explain them. Second, there is renewed debate on methods and reasons for comparing cities. This project, based on extensive work over some decades in four different cities on three continents (Dar-es-Salaam, Gauteng (including Johannesburg and Pretoria), Paris, and São Paulo), seeks to review these fields, and to develop a new argument on what I prefer to term ‘city studies’. The chosen cities, or rather city-regions – for all stretch well beyond their original areas – by no means claim to exhaust the variety of cities on their own continents, let alone others, and will focus on selected themes of the social and geographical nature of the expansion of cities; instabilities and contests over forms of city government; and imaginaries of city futures carried and acted on by different groups of people.