I ran across this author page which just looks kind of scammy. The "books" are reviews with links to Amazon, except when you click on the link, Amazon says the page doesn't exist.
They are "real" "books" in the sense that they were published, and available for purchase at one time, whether or not they are still available to purchase. They're reviews of bestselling books. Probably they're published with the intent to scam - the author or publisher is hoping people will confuse them with the book they are reviewing, e.g. Gone Girl, and buy the 30 page review instead of the book. There's a lot of this type of "book" out there, for sale, and on GR. They are certainly scammy, but also legit by GR definitions.
https://www.goodreads.com/author/show...