the Traditional library

From an elementary perspective, libraries exist to loan readers books. It would be impractical do this by letting visitors walk up and down the aisles, opening each book in sight to decide whether they want to check it out. Instead, libraries provide readers drawers full of cardboard cards that represent books. Each card describes one book; a visitor reads the description on the card and decides whether to check out the book. The cards with the book descriptions on them are called citations.

A typical citation provides a book's title and subject, author, publisher, copyright, publication date; it lets a visitor know whether it's a work of fiction or non-fiction. A citation may also give a description of a book's contents. Armed with this knowledge, with the assistance of a librarian, a visitor is equipped to find the cited book on the shelf and look through it before finally deciding whether to check it out.

If the visitor decides to check the book out, the librarian pulls the book from the shelf and brings it to the desk on a library cart, usually with other books for other visitors, and signs them out. The librarian also uses the cart to file returned books on the shelf.

A book mentioned in a citation is a holding and a library's collection of books is referred to as its holdings. Holdings are not citations; citations describe holdings. Holdings are the books, maps, pictures, and other resources stored on the library's shelves, usually in another part of the building, not in the part of the building where the catalog resides. Books and other holdings are shunting back and forth between the Front Desk, where patrons sign out books, and the shelves in other rooms where holdings are stored. Sometimes a book mentioned in a citation belongs to the holdings of another library, from which it can be borrowed.

In a traditional library, citations are kept in a library's card catalog, where visitors can take a close look at them. Before computers came of age, citations typically were printed on 3X5 cards; the cards were stuffed into long and narrow drawers which were crammed next to each other, row upon row, into the gliders in a wooden or metal cabinet. The collection of 3X5 cards in drawers is called the library's card catalog. Today, some libraries still store citations in a card catalog; but more and more, libraries are storing citations in electronic databases.