Fred Mcgraw Donner 
The Early Islamic Conquests [PDF ebook] 

In this contribution to the ongoing debate on the nature and causes of the Islamic conquests in Syria and Iraq during the sixth and seventh centuries, Fred Donner argues for a necessary distinction between the causes of the conquests, the causes of their success, and the causes of the subsequent Arab migrations to the Fertile Crescent.
Originally published in 1982.
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