Phrase “Up in the stacks”. What would this phrase mean?

Question

A textbook which introduces vocabularies that could appear on the day of the test (TOEFL) gives me a below sentence.

It sounds like the staff at the circulation desk knows you pretty well. These days I'm mainly using the reserve desk and the reference section. My biology professor puts a lot of articles on reserve, and then there're these big reference volumes -- like The Encyclopedia Of Biology -- in the reference room that he wants us to read. You can't check those out. So I usually take them to a quiet desk up in the stacks and read them there.

I "conquered" several parts which are easy to native speakers, but I finally gave up when I came across the bold part. (Googling didn't help). Could you please help me what up in the stacks mean, in (probably) this context?

Answer 1

It simply means "up around the bookshelves". From Wikipedia:

In library science and architecture, a stack or bookstack (often referred to as a library building's stacks) is a book storage area, as opposed to a reading area.

And, from an "Ask a Librarian" column:

'Stacks' are the open shelves of library books. If the catalogue says a book is in the stacks, then it's on a shelf in the branch indicated in the catalogue.

The precise meaning of a preposition depends on the context. In this case, if a book is "up in the stacks," that means it's on the bookshelf, but if a person in "up in the stacks," that means they are sitting on a chair or at a table that is surrounded by bookshelves, or perhaps standing in the aisle looking at a book.