This one has unfortunately been a little bit of a slog. I bought it after seeing the author interviewed at the HNS conference, which proves that personal appearances actually sell books, at least anecdotally. (!)
I wanted to love it! It isn’t bad, it just isn’t great. I would give it 3 stars out of 5, and I saw that mostly I agree with the other people who gave it 3 stars, and some people who gave it 4, that it is a little weighed down with too much historical research stuffed into it. There are a lot of what I like to call facty asides, where the writer takes the reader out of the story to explain something to them. It slows the pace and makes it harder to stay invested in the characters. It has a prologue that should have been cut, because it is not part of the main plot. There are too many subplots and threads to maintain narrative drive and it makes even mystery lovers like me, not care who did it by the time they get to the end. They just want it to be over.
If you are the kind of reader who really wants the facty asides and doesn’t care about the story, then maybe this is for you. It is written by a successful author, so who am I, other than a reader, to say meh? I will just let you know that it took me way too long to finish this and I only finished it because of sunk cost fallacy, so readers like me, beware.