"The Revisionists" was not at all what I'd expected, yet I couldn't put it down -- hence the four stars. 
 I have a soft spot for all things time-travel, and the basic synopses I'd read of this book seemed to put it squarely into that genre: Main character Zed works for a post-disaster society at some point in time several centuries from now. In the "Perfect Present", there is no war, no racial tension, no hate. Zed's government agency works to keep the perfect present perfect, by sending agents into the past to thwart "hags" -- historical agitators -- whose mission is to stop disasters (think 9/11, concentration camps, etc) before they can happen, on the assumption that all these calamities were a necessary step in history in order for the perfect present to come to be. 
 Confusing? You bet. 
 And strangely, that's not at all what this book is really about. Much more than anything else, I'd describe "The Revisionists" as an espionage-thriller set in DC, filled with intrigue, shadowy quasi-governmental intelligence outfits working against one another, multiple layers of pawns and spymasters, and a reality that slips and shifts from chapter to chapter. 
 This is not a sci-fi book, when you get right down to it. Zed's mission is the driving narrative, yet we get no information whatsoever about the mechanics of his time travel and only the barest of descriptions of some futuristic technology. Without saying anything that might inadvertently be a spoiler, I will say that the entire time travel premise is not necessarily what it appears to be, depending on how you choose to interpret certain events and passages. 
 I was fascinated by this book, and it will probably take me some time to mull over all the twists and turns and come to terms with what may or may not have happened. I do recommend "The Revisionists", although I worry that its perfect target audience -- people who enjoy a good spy thriller -- won't ever discover it if it continues to be described as a time-travel novel.