Not good.
When you buy a reference book, I think you need to check who the author is, and check the credentials of that author.
And of course, there will need to be laws in place to require books with non-human authors to be clearly identified as such with an obvious disclaimer. Cigarette packets have a warning: "Smoking cigarettes can seriously damage your health." AI generated books should have a legally mandated warning: "Any and all content in this book might be fiction. Do not trust anything it says."