ABSTRACT

This entry outlines the history, application, and nature of the Universal Decimal Classification (UDC). It explains its structure, management, revision, and the many changes that have taken place since the Task Force for UDC Development reported in 1990, and the UDC Consortium was formed. This led to the creation of the machine-readable database, or Master Reference File (MRF), consisting of some 66,000 terms, which forms the basis of all published editions and is revised and updated annually. Revision procedures and applications in an online environment are noted and the potential for future development discussed.