Shahab Ahmed tells us up front that he is not going to answer the question "what is Islam?". And of course, he does not really do so, but the title (misleadingly) suggests that he will, and in the course of the book, he comes perilously close to trying (and failing) to do so without outright saying he is going to do it. In short, Shahab himself seems confused about what he is trying to achieve here. The book is a description of some (but certainly not all) aspects of Islamic culture as it developed and expanded, especially AFTER the initial Arab phase of empire building. And it is a long argument with various seen and unseen opponents who want to define Islam as some ONE thing. In the course of this argument, Shahab wants to show that Islam was very varied, but he also wants to show that it is not infinitely varied. In the course of an overly long book, he manages to show that Islamicate societies (a term he does not really approve of) had a very wide variety of beliefs and practices, though they also remained anchored within a certain tradition and in continuous argument with particular foundational texts. All of this may be a surprise to extreme puritanical Islamists AND to more or less ignorant anti-Islamists, but should be no surprise at all to anyone else. Why wouldn't there be a lot of variety? Anyway, if you happen to spend your life arguing with people who have a very monochromatic view of Islam, then you can keep this book handy in order to prove otherwise. It is good for that.