I recently saw https://travel.stackexchange.com/questions/39245/looking-for-a-book-only-remember-cover-explorer-standing-on-mountain-looking-a
This question was vague, had only few clues and it was hard to come up with a valid response for even experts from our group, however I was surprised at the reason why it was closed.
"This question appears to be off-topic because it is about a book", shouldn't it have been closed as being "Too Broad", the reasons for close are also indications for future questions and hence I just felt it would be worthwhile clarifying.
Note: I did go through Are questions about book recommendations really offtopic? however there the issue was it wasn't specific about the requirement itself.