WITH the publication of these two volumes, the historical study of Islam in sub-Saharan Africa has reached its maturity. Drawing on five decades of scholarship since the professionalization of African history, and the long traditions of Islamic and African studies before that, these works – one the first truly usable textbook survey of the field, the other the first comprehensive reference – are both a successful culmination of what has gone before and guides to the paths ahead. In some cases the authors' and editors' careers are virtually synonymous with the field as a whole, as with the late Nehemia Levtzion, and all are among the acknowledged authorities on their specialties. David Robinson, author of Muslim Societies in African History, is one of the few who have established themselves as authorities on both the precolonial and colonial periods, and his work is central to active debates in each subfield. The individual and collective stature of Levtzion and Randall L. Pouwels, editors of The History of Islam in Africa, along with that of the twenty-two other contributors, makes the authority of the volume unprecedented.