I finished two books not long ago, both on Islam. While both books were pretty introductory, they differed from each other in several ways. John Esposito's 2002 book What Everyone Needs to Know About Islam is a very straight forward, almost Q and A type of book and in it, Esposito addresses numerous topics and issues relevant to Islam and its role in the world. Esposito, while not a Muslim, is a Professor of Religion and International Affairs at Georgetown University and the author of numerous books including The Islamic Threat:Myth or Reality and Who Speaks For Islam: What a Billion Muslims Really Think.
The other book I read was Ziauddin Sardar's recent book What Muslims Believe:The Roots and Realities of Modern Islam. Sardar, is a prominent Muslim intellectual, academic and author of over 40 books on Islam. While Esposito's book is more direct and straight forward, Sardar's book is more philosophical, perhaps even theological. Although very introductory in its scope, I found Sardar's arguments to be quite sophisticated. His book complemented Esposito's book rather nicely.
After I finishing
these two books, I took the opportunity to supplement my reading by reading several religious tracts courtesy of the Muslim Students' Association of Portland State University. They were kind enough to supply me with several brochures from Why Islam ?, as well as an introductory booklet from the Islamic Affairs Department of the Embassy of Saudi Arabia and another introductory booklet published by the Darussalam organization.