Sloppy, self-indulgent, and pretentious.
1. The pretentious excerpts that start each chapter are just ridiculous. They seem to exist only to indulge the ego of the author. Enough, already.
2. The book is overly long for no good reason. The mystery is incomprehensible. And it's over-written. Where's the editor?!
3. The vast majority of the book is focused on the unrequited romantic relationship between Strike and Robin. It's like sitting in a middle school cafeteria with two selfish, temperamental, and humorless middle schoolers. It's relentless - literally repeated on almost every page - and over the course of the book this renders both characters increasingly unattractive. We never see a compelling connection between these two. In the few moments we start to, Robin gets offended or Strike growls and swills down whiskey. They are a collective bore!
4. Robin is an awful person and a lousy detective. Her constant dishonesty with the men in her life and the obsession with her emotional over reactions make her careless and ineffective. I wouldn't hire her to find my keys.
But surely Strike will rescue her! As he always does.
And she is downright cruel to Murphy. He's got his own issues, certainly. But Robin never tells the truth to anyone. And yet, to her, she is always the victim. Insufferable.
Rowling needs to do better with her female detective. For God's sake, give her a personality!
5. The original premise of the mystery is interesting, indeed. The woman who hires them is intriguing. Then we almost never see her again. Over the course of the book we are subjected to endless conversations filled with incomprehensible information, often about Freemasons. All immediacy and drama are gone. It's a slog.
It's a real shame because the first book in the series was very good. It had energy and kept readers interested.
Ah well. Nothing lasts forever, not even a J.K. Rowling book.