Hela Ouardi, if translated in English, would be a excellent place to start. The main strength of her works is that she relates Islam birth and growth from both Shiites and Sunnis sources. Usually, people only know the Sunnis' version of this story, yet Shiites materials help to shed some light on the whole matter.
I remember as especially interesting that Umar, just after Muhammad's death, pretended that Muhammad will rise from the dead, arguing from a verse of the Qu'ran that most Muslims who were present seemed to ignore.