The growth of cities is one of the most significant aspects of the contemporary transformation of African societies. Cities in Africa are the sites of major political, economic and social innovation, and thus play a critical role in national politics, domestic economic growth and social development. They are also key platforms for interaction with the wider world and mediate between global and national contexts. Cities are variously positioned in global flows of resources, goods and ideas, and are shaped by varied historical trajectories and local cultures. The result is a great diversity of urban societies across the continent. Cities in Africa are not only growing rapidly but are also undergoing deep political, economic and social transformation. They are changing in ways that defy usual notions of urbanism. In their dazzling complexity, they challenge most theories of the urban. African cities represent major challenges as well as opportunities. Both need to be understood and addressed if a sustainable urban future is to be achieved on the continent. The Urban Cluster of the Nordic Africa Institute, through its research, seeks to contribute to an understanding of processes of urban change in Africa. This discussion paper by Professor AbdouMaliq Simone, commissioned by the Urban Cluster, is a valuable contribution to shaping the research agenda on urban Africa.