The Origins of the Islamic State: Being a Translation of kitaab futu al-buldaan of Abul-l Abbas Ahmad ibm Jabir al-Baladhuri, by Philip K. Hitti

This book is one of the most reliable sources on the beginnings of Islamic statehood. It covers the wars of Prophet Muhammad, the ridda wars, the conquests of Syria, Armenia, Egypt, the Maghrib, and lastly, the occupation of Iraq and Persia.