A catalog is an inventory of materials in a library. These materials such as books, magazines, newspapers and videos are often referred to as the library's "holdings." The catalog enables users to search for and locate materials held by a library. Many catalogs, including the UNC Chapel Hill Libraries' catalog, are available on the Internet.

The catalog consists of individual catalog records for each item in the library. A catalog record lists information about the item's author, title, content, physical attributes, and location.

Like other library holdings, manuscript collections have individual records in the catalog.

Some large collections have multiple catalog records to describe individual series.