Screenshot shows 44 pages, so definitely not a full length novel.
I'm not sure why y'all are calling it a novel; it at least purports to be nonfiction. (Is it a comment on the propensity of LLMs to hallucinate?)
No one is calling it a novel. "Novel" is just being used as a measure of length.
I seem to recall doing some math and finding out the limit for some models of LLM was pretty close to that. If so, this book is likely the result of a single prompt, which seems to me like a lazy way to be lazy.