Ronald Segal's book /Islam's Black Slaves/ is a decent starting point, 
but sooner or later a reader who wants to learn more about this subject 
will have to consult the works of specialists who know Arabic. A 
well-edited collection of documents, many translated from Arabic, is 
John Hunwick and Eve Troutt Powell, /The African Diaspora in the 
Mediterranean Lands of Islam/ (Princeton, 2002). Hunwick has been 
instrumental in a global network of scholars, states, and NGOs who are 
attempting to preserve thousands of irreplaceable Arabic manuscripts in 
private libraries in Timbuktu.

Doug Deal
History/SUNY Oswego