The Sudan is a broad belt of grassland that stretches across the West African continent. The word comes from the Arabic Bilad es Sudan, “the land of the Blacks.” The Sudan's northern fringe, the Sahel, merges into the desert and has long been influenced by exchange with desert peoples. To the south, it merges with woodland and forest and with mountainous areas like the Futa Jallon of Guinea. Of all areas of Africa, it is the one that has seen the longest development of agriculture, of markets and long-distance trade, and of complex political systems. It was also the first area south of the Sahara where African Islam took root and flowered. This study is concerned with three former French colonies: Senegal, Guinea and the agricultural part of Mali.

For much of modern history, the western Sudan has been a source of slaves for other parts of the world. Early in the first millennium, it began providing a steady stream of slaves for the Mediterranean world and, with the coming of the Portuguese in the fifteenth century, people were directed into the Atlantic slave trade.