There's actually a lot of very excellent scholarly literature on early Islam and its formation and on pre-and-early-Islamic Arabia and the Middle East in general. For a very solid introduction to the general topic of the formation of Islam, I would suggest Muhammed and The Believers: At The Origin of Islam by Fred Donner; it's written for a popular audience and doesn't presume too much background knowledge but it an very excellent and concise summary of what our current understanding of early Islam is and has a good deal of solid bibliographic information to give you a starting point for further reading. You may also find Donner's book The Early Islamic Conquests of interest but bear in mind that it is a somewhat older book. If you are interested in further reading on specific subjects, feel free to check the booklist or inquire within.