Library of Congress Control Number

History
– LCCN numbering system in use since 1898
– Originally stood for Library of Congress Card Number
– Also known as Library of Congress Catalog Card Number
– Cards of bibliographic information sold to other libraries
– LCCN used to identify unique records

Format
– Number includes year and serial number
– Two digits for 1898 to 2000, four digits from 2001
– Three ambiguous years distinguished by serial number size
– Experiment between 1969 and 1972 added a check digit
– Serial numbers are six digits long with leading zeros

Related Concepts
– Accession number (library science)
– Authority control
– Books in the United States
International Standard Book Number (ISBN)
– Library of Congress Subject Headings

References
– Types of Numbers Found in LC Catalog Records
– Structure of the LC Control Number
– Library of Congress Update for 2008 ALA Annual Conference
– General Questions About LCCN Permalink
– The LCCN NamespaceSources: https://en.wikipedia.org/wiki/LCCN_(identifier)