By way of a p.s. to this discussion:   If you read Lovejoy or other 
works that discuss the Islamic trade in slaves from Africa to the 
Middle East, you may be--as I was--amazed to learn the huge numbers 
that were involved.  Millions of Africans were caught up in this trade, 
though always many fewer than in the Atlantic trade (and it's worth 
mentioning that in the Atlantic trade, North America was a minor, 
peripheral destination: the vast majority of slaves went to the 
Caribbean and, later, to Brazil).

The critical distinction between the Islamic/East African and Atlantic 
trades, however, from the standpoint of historical consequences, is 
that the children of African slaves in the Middle East, and even some 
of the slaves themselves, were fully incorporated into society.  Such 
incorporation has been the norm in most slaveholding societies 
throughout history.  It is the race-based, perpetually heritable 
dimension of Atlantic slavery that sets it apart historically from 
other slave systems and determined its role in New World societies.

--Jurretta