As far as sociological/historical books on racism go, this was not my favorite. I found the stylized narrative to be distracting, and the rhetorical flourishes made me cringe. "The ash rose from the crematorium into the air, carried by karma and breeze" is the kind of sentence you expect to find in an undergrad creative writing class, not in a book by a winner of the National Book Critics Circle Award. It, like many sentences in this book, is painfully overwritten, and instead of leading the reader to an organic emotional revelation through good writing, it tells us what we should be feeling via its plodding language.
Additionally, Wilkerson's tendency to strip names & identifying details from her real-life examples of caste in action gave them a gauzy, unrealistic air. To be clear, I do not think she made anything up, but the way they were presented made them feel made up, like they'd been manufactured to illustrate a point in the hopes that a parable would have more emotional impact than a bare-bones fact of life. As someone who grew up hearing sermons every Sunday morning in which an evangelical preacher artfully plucked stories from books, movies, and news headlines and whittled them down to their bare-minimum components in order to make his point, I found this style frustrating. It felt like I was being led along a path of pre-labeled emotions, rather than invited into a re-visioning of history that challenged what I've previously learned.
I also wish Wilkerson had been more specific in describing this American caste she spent an entire book talking about. As it is, we have white people on top and Black people on bottom, with other marginalized groups an amorphous jumble in the middle that she remembered to mention when it served her point. It is not one person's job to write the be-all, end-all account of racism in America, but a little more definition would have gone a long way. I was particularly frustrated with the way indigenous people were left pretty completely out of the narrative, save for a couple off-hand mentions of genocide here and there. (This is not a new practice; had I not been reading An Indigenous Peoples' History of the United States at the same time, I'm not confident I would have noticed it, so thorough is the colonizing tendency to erase Native history.)
In conclusion, I'm sure many people will find this book helpful; the chapters on Germany and the way the Nazis studied American society to devise a way to make white supremacy legal were eye-opening, and I don't regret the time I spent with it. Overall, though, it's a bit of a disappointment. If you're going to read it, I'd encourage picking up Minor Feelings by Cathy Park Hong, Good Talk by Mira Jacob, and any book in the Re-Visioning America series to read alongside it