Machine derived contents note: Figures -- Preface and acknowledgements -- 1. Introduction -- 2. Concepts and questions -- 3. Corridor or cul-de-sac: the middle Nile -- 4. The benefits of isolation: the Ethiopian highlands -- 5. An optimal zone: the West African savanna -- 6. Brilliance beneath the trees: the West African forest and its fringes -- 7. The edge or the centre: cities of the East African coast -- 8. A question of economic basis: Great Zimbabwe and related sites -- 9. The problem of archaeological visibility: other precolonial cities and states in tropical Africa -- 10. What are the common denominators? -- Bibliography -- Index