So, I’m not really sure how to say this, but I think this book was written by an Artificial Intelligence (AI). Not a clever one, but one that was trained by reading bad murder mysteries from the 1940s, and travel books. I’m not gonna lie, I only got half way through, and because I got a free, pre-publication (PDF) copy I tried, I really, really tried, but oh my lord this book is soooo bad.
I’m gonna lay this out for you as best I can, but I have several reasons for thinking it was written by a non-human entity.
1. This is a picture of the author:

^^^^Does this look like a real person to you? Like, yeah, sort of “educated” and “hipster” and “sexist” (more on that later), but like a mash-up of all those things into one tiresome bro, jazzed up as a photoshop pencil sketch. Y’all, his name is “Maxwell Jacobs.”
2. This passage from early in the book:

^^^^Like, that’s some blatantly awful stream of consciousness writing right there. The main character, ahem Harry Hoffman, is constantly thinking a thing, then saying a thing out loud to himself. I think it’s an attempt to help readers figure out that he’s an unreliable narrator, but it just comes across as stupid and ludicrous… and tedious.
3. According to the “author’s” bio, he got the idea for writing this book while traveling around Europe. About 25% of the story is about the locations the main character is in. Not just observational or atmospheric information, more like a travel book would describe a city like Zurich, or Paris, or Lake Como. As in, I just got a job copywriting hotel blurbs for Booking.com, what should I say to make this run-down flea-bag hotel sound like a nice place to visit? Captain Obvious.
4. The main character, Harry, kills several people in the novel, and comes across as a complete sociopath who leaves his wife and child, has affairs with multiple women (at least one of whom he murders), then writes a book about what he’s done, and has to apologize to said ex-wife before the book is published. So WTF was this actual author doing while he was traveling around Europe?
5. Speaking of women:

^^^Does that sound creepy and sexist to you? It totally does, doesn’t it.
6. In Book II Harry reconnects with a woman he had an affair with in Venice (in Book I), who disappeared unexpectedly. Her name was Cleo, and she was married and had a daughter. Except, when she appears again, she needs a place to stay to keep away from her husband, who she had been avoiding, by faking her death, but she wanted her daughter back, so she came back to life. Also, her real name is Maria, not Cleo. Also, she comes to Zurich to find Harry, but unless I’m completely crazy (or fell asleep reading), I would swear he had just moved to Paris. At this point I was so confused, but I just didn’t care anymore, so I gave up.
And here we are.
I’m completely convinced that no human being could write such horrible dialogue. Or locations. No person in the story ever eats, they just drink constantly, and smoke cigarettes. No dates are given, so “the stinking war” Harry fought in might be WWII or ???. Harry kills people and never gets caught, even though he murders a woman in his hotel room and we never know how he got away.

Dear readers, that is just the first half of the book, and it’s only 300+ pages long. You might be made of stronger stuff than I, but I also have these on my bedside table, waiting to be read (plus, like ten more on Kindle):
So I’m going to move on. I’ll leave it to you to solve the mystery of whether the author is real human boy or a badly trained AI…