Open-shelf: refers to the library stacks are open to readers, so that readers can find the books to borrow directly from the shelves without looking up the catalogue.

Closed shelf: refers to the way that readers borrow books by consulting the catalogue, copying the book number or dictating the title, and the administrator looks for books on their behalf. When the reader returns the book, the staff will put it back on the shelf. Closed bookshelves are good for protecting books.