This list is called the shelf-list.

It is commonly kept on sheets, but many librarians believe it best kept on cards; a card for each different book.

It is a catalog of all the books in the library arranged in the order in which they stand on the shelves.

It is a subject-index of the library.

It is indispensable in the work of properly placing, class-numbering, and author-numbering new books.
It is a list from which it is very easy to check over the library and learn what books are missing or out of place.