Defined card catalog

A card catalog is a physical listing of all of the contents of a library, organized with a single card for each item in the library. The cardcatalog was a familiar navigational hazard and blessing in all libraries well through the late 20th century, when physical cardcatalogs began to be displaced by computerized versions. Some libraries retain their card catalogs, often as sentimental mementos, and a few actively maintain their card catalogs: this is most common in small, remote libraries.