I initially bought this book because I was impressed with another "Very short introduction" entitled "The Koran" by Michael Cook. I thought that "Islam" would be as good, but I was disappointed. Instead of a thoughtful and insightful book, I found "Islam" to be a hodgepodge collection of facts, opinions and speculation that brought me no closer to understanding Islam than I had been before. Ruthven is best in the brief sections when he sticks to comparing religions (which is apparently what he does for a living). However, the author seems to misunderstand many aspects of Islam, and makes several significant factual errors- the greatest of these perhaps is the assertion of the widespread influence of Sufism on Islam and the Muslim world as a whole. If you are thinking of buying this book in order to get an understanding of Islam, forget it. Buy "The Koran" instead, and you will get a much better understanding (and book) at the same price.