This book is a (weak) five-star right up to its last couple of chapters. Informative, well-written (if somewhat breezy) and detailed. The interpretation is... debatable, at many points, but a history book that forces you to think about interpreting events can't be faulted for that, right?
Reading the last two chapters and epilogue are a bit like finding a fly in the soup, after you've eaten most of the soup. McMeekin's views on the meaning of jihad in Islam and the origins of anti-semitism in the Middle East are the sort of discredited Iraqi Freedom-era propaganda I expect to see in a Reddit thread, not a serious (if popular) book of history. The "Clash of Civilizations" nonsense would not be out of place here.
Weirdly, McMeekin does all the necessary discrediting himself, in the earlier chapters of the book. The abject failure of the German-backed jihad projects against the British and French Empires tell us all we need to know about the relative importance of "Islamic holy war" vs good old styled Nationalism.
I'm letting this one have four stars if read as a appendix to Fromkin's far, far better Peace to End All Peace, as the information presented here fleshes out and contextualizes Fromkin's book, which focuses largely on the Entente's role in shaping the post-war Middle East, while this one is largely about the pre-war and wartime German project for the same area.