The LCCN Namespace

November 2003

Network Development and MARC Standards Office
Library of Congress


The LCCN namespace consists of identifiers, one corresponding to every assigned LCCN (Library of Congress Control Number). Any LCCN may have various forms which all normalize to a single canonical form; only normalized values are included in the LCCN namespace.

An LCCN is an identifier assigned by the Library of Congress for a metadata record (e.g., bibliographic record, authority record). LCCNs have three components: prefix, year, and serial number. The prefix is optional; if present, it has one to three lowercase alphabetic characters. (Prefixes are maintained in a controlled list.) The year is two or four digits. (For 2000 and earlier the year is two digits, for 2001 and later, four digits.) The serial number (after normalization) is six digits. (An un-normalized LCCN may have a serial number of 1-6 digits, which is left-filled with zeros when normalized.)


Syntax of a Normalized LCCN
A normalized LCCN is a character string eight to twelve characters in length. (For purposes of this description characters are ordered from left to right -- "first" means "leftmost".)
The rightmost eight characters are always digits.
If the length is 9, then the first character must be alphabetic.
If the length is 10, then the first two characters must be either both digits or both alphabetic.
If the length is 11, then the first character must be alphabetic and the next two characters must be either both digits or both alphabetic.
If the length is 12, then the first two characters must be alphabetic and the remaining characters digits.


Normalization of LCCNs

An LCCN is to be normalized to its canonical form described in the syntax description above, as follows:

  1. Remove all blanks.
  2. If there is a forward slash (/) in the string, remove it, and remove all characters to the right of the forward slash.
  3. If there is a hyphen in the string:

Examples:


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Library of Congress Help Desk (11/10/2003)