Towns and cities existed throughout Africa’s past. However since the late twentieth century Africans are witnessing a historically unprecedented transition from living mainly in rural areas to residing in towns and cities. This chapters explains the key concepts of the urban growth process and sets Africa's urbanization into a historical and global perspective. The second part of the chapter explores the driving forces behind Africa's ongoing urbanization process, and asks whether economic development and urbanization have moved in tandem. Finally, welfare consequences resulting from rapid urban growth in Africa without sufficient economic growth are discussed.