The Library of Congress Control Number (LCCN) is a unique identifier assigned to each cataloged item in the Library of Congress. It helps libraries and researchers easily locate and reference specific works, such as books, music, and audiovisual materials. The LCCN is typically a combination of the year of cataloging and a sequential number. LCCNs are used by libraries worldwide to streamline cataloging and improve access to information. By providing a standardized way to identify items, the LCCN enhances the organization of collections and facilitates interlibrary loans and resource sharing among institutions.