This gives rise to a question: Is there such a thing as a bad book? And then: If so, what would it be?
The answer has to be yes, if there is a standard that qualifies some books as good, we must consider any that fail as bad. Beyond that, good and bad must remain matters of personal taste; some will love what others despise or condemn. That said, one kind of book is always bad, and the more people enjoy it, worse it becomes. Books filled with misinformation, especially when used to propagandize or proselytize malice, harmful causes, power plays, thievery, murder, incite riots, or whatever else may interfere with social justice. Whoever reads them is worse off than whomever cannot read.