The book content itself is deliberately free of AI-generated prose. Drafts may start anywhere, but final text should be reviewed, edited, and owned by a human contributor.
People have the illusion of reviewing and "owning" the final product, but that is not how it looks like from the outside. The quality, the prose style, the errors that pass through due to inevitable AI-induced complacency ALWAYS EVENTUALLY show. If people got out of the AI bubbles they would see it too, alas.
We keep reading the same stories for at least a couple of years now. There is no novelty anymore. The core issues and problems have stayed the same since gpt3.5. And because they are so omnipresent in the internet, we have grown to be able to recognise them almost automatically. It is no longer just a matter of quality, it is an insult to the readers when an author pretends that content is not AI generated just because they "reviewed it". Reviewing sth that somebody else wrote is not ownership, esp when that sth is an LLM.
In any case, I do not care if people want to read or write AI generated books, just don't lie about it being AI generated.