In this first major historical study of Islam among the Swahili, Randall Pouwels shows how Islam and other aspects of coastal civilization have evolved since about AD 1000 as an organic whole. Coastal Africans, he argues, simply adopted Islam as the spiritual vehicle best suited to their expanding intellectual needs and to meeting the opportunities presented by their physical and cultural environment. The culture and religion that developed were strong, rich, supple, self-assured. yet capable of accommodating change where it was unavoidable or preferable. All these characteristics were put to the test in the nineteenth century, when coastal peoples were subjected to intense Arabizing and Westernizing influences. Pouwels demonstrates how local people went on asserting their own traditions while assimilating what they chose from both worlds. East African Muslims, therefore faced the twentieth century divided on issues of local cultural autonomy and the need to conform to external cultural pressures.