If it takes 10,000 hours, a real slow reader needs to read only one book.
How many books to read before you're a master?

I never "got" "Catcher in the Rye." In fact I found it a bit repulsive. "Franny and Zooey" at least made me laugh in places though the characters tended to be somewhat pretentious and self-absorbed. For some reason, "Catcher" always reminded me of "Poem on an Underground Wall."

If it takes 10,000 hours, a real slow reader needs to read only one book.
yeah like the War and Peace or all 3 books of Lord of the Rings.

I never "got" "Catcher in the Rye." In fact I found it a bit repulsive.
Maybe you should have read it as a teenage boy ;)

At least one. After all the versions of the bible, I suspect the least read books that are bought are chess books.

I think as the amount of chess knowledge and understanding increases whatever the number is
increases as competition grows ever stronger and more knowledgible. Dozens - hundreds...? But other things like practice against masters and tournament competition as well as possibly lessons come into play. On tactics alone I have worked through 15 - 20 books and am only adequite at the NM level. Talent plays a large part also. Some thoughts from someone who earned the US NM title.

never been a fan of books. only one i ever touched besides opening books as reference was silman's endgame guide.
postmortems of your games, tactics, etc are far more important.

It's important to keep in mind that simply reading books doesn't make one a master. I've known top GMs who have read just a few chess books in their life and bookwormish A-class players who claim having read over 100 books. A lot depends on how the quality of the books, how deeply you understand the material, and how you put it into practice.
Best comment thus far.
Rule of the Bone by Russell Banks is Catcher in the Rye for today's 30-somethings.