books.google.co.uk - Authoritative and carefully researched history of Islam under the first four righteous Caliphs. Refutes the myth that Islam was spread by the sword. Wonderfully free of all sectarian influences....http://books.google.co.uk/books/about/The_Early_Caliphate.html?id=flg-UX6fOdkC&utm_source=gb-gplus-shareThe Early Caliphate
