Here's why this works:
* Obscure means unknown, not famous, or difficult to understand.
* The sentence emphasizes the rarity and potential difficulty of understanding the book.
Here are some other ways to use "obscure" in a sentence:
* "The detective investigated the obscure details of the case, searching for clues."
* "He had a passion for obscure movies that few people had ever heard of."
* "Her writing style was so obscure that it was difficult to follow her train of thought."