This is a great history of the sharia, detailing the emergence of the hadith, the four schools of Sunni jurisprudence, and the Twelver Shia. While this represents the majority of the Muslim word, important schools like the Ibadi are absent. Kadri also details the roots of some extremist Islamic thought from Hanbal to Ibn Taymiyya to Wahab through to elements of the Muslim Brotherhood to Al Qaeda. (The book was written before ISIS became a player). Fewer dots are connected in the history of Shia jurisprudence, though it is detailed as well.
Kari includes the token—sometimes gratuitous—reminders that, by comparison, contemporaneous Europeans were worse whenever we read something that sounds too awful, at least in the history. The conclusion has a similar kumbaya tone, which doesn't quite undo all of the work done in the previous chapters. Kadri, like many Western intellectuals, is capable of making criticisms of extremism in situ in other countries—he points out the utter unreality of decisions by judges in Pakistan and Iran, for example, or in his mentions of how harsh penalties were mitigated with legal fictions such as three-year-long pregnancies—when the situation turns to Muslim minorities in the West itself, somehow, anyone who is concerned is to be mocked.
For example, without further discussion, Kadri mentions on a couple of occasions the laws in Western Europe banning women from wearing the veil. Kadri assures us that most of the women subject to this law want to wear the veil and are more oppressed by the law itself. In other words, French revolutionary values in France should take a backseat to an Islamic Neo-Orthodoxy. In France. In other words, Islamic orthodoxy in Saudi Arabia should be criticized, but in France (or the US, or the UK) it should not. Similarly, when discussion arbitration laws in the US, Kadri mentions that Orthodox Jews use batei din just like Muslims might use sharia arbitration. No discussion is made about whether private courts are a good idea, just that if others are doing it, it's ok for Muslims. In other words, relativism for the West, liberalism for the East.
Frankly, I wonder if this is Kadri's real belief. This tone doesn't permeate the book until its last pages and they almost seem an afterthought. The historical portions are an honest and fair historical account of the development of the sharia—which, like many histories of Islam is colorful, vivid, and detailed from the seventh century to the thirteenth and then merely skeletal for the next 500 years.
It is critical for Westerners who want to understand more about Islam that they can't pick and choose a few verses from the Quran and seek to extract some meaning from that. The Quran is a relatively short work. But unless you understand how it's interpreted, and know something of the thousands of Hadiths that complement it, and the jurisprudential rules that make them all work together, you will be learning about the Quran only and not Islam.
This book does an excellent job of doing that work and is an excellent critique of how those rules are implemented in the East.
Edit: One concern I have with this book is its reliance on official statistics. Just because the state only performed one execution, how many people were killed extrajudicially? How many of those on religious grounds? Those may be unanswerable questions, but without those answers, the claim Kadri makes can't be made.