If I say “You can borrow any book in the library.”, does the countable noun “book” denote a concept "book" which in turn is used as an uncountable noun?

On the other hand, the sentence “Do you have any books in your room?” sounds natural to me because I can construe the word "books" as tangible object.

查看翻譯

I don't think that 'book' means just 'one book' as a countable noun.
People say 'a book' as a countable noun in this sense.
For example, if you say: “What kinds of 'book' do you like?”
This expression is awkward by the fact that there are only three types of book:
“hardcover or paperback or Kindle”
So you should say:
“What kind of books do you like?”
= “What genre of books do you like to read?”
"What kinds of books do you like?
= "What genres of books do you like to read?

You suggested that the word 'book' in the context "You can borrow any book in the library." denotes "one book", but in the context of a dialogue below the word "apple" denotes a concept "apple" which is in turn an uncountable noun.

A: "what kind of apple can I use to make apple pie?"
B: "Any apple will do!"

No single book is true: that is, no single book contains the truth, the whole truth, and nothing but the truth. Neither does any one chapter, verse, or quotation. Or this essay.

Reality is too robust to be contained between covers, or encoded within a finite pattern of abstract symbols. In what sense, even the most generously metaphorical, could a few hundred inked-up sheets of paper “contain” the past, present, and future of over 100 billion galaxies? Stephane Mallarmé said beautifully that “the world exists to end up in a book,” but that book has never been written, and the world goes on without it.

http://bigthink.com/book-think/no-single-book-i...

All right. Thank you very much for your comments!