The Library of Congress Control Number (LCCN) is assigned by the Library of Congress (LC) to each LC catalog record. LCCN's are often assigned to publishers in advance of publication so that the number may be printed in the item or used in advertising. The LCCN is unique to each item and is an important access point.
The LCCN is most often found on the verso of the title page within the "Library of Congress Cataloging in Publication" (CIP) area. The LCCN is occasionally found in other preliminaries or the colophon.
Enter only true Library of Congress control numbers in the 010 field.
Never record look-alike numbers from foreign publications in 010.
Look-alike numbers appear in foreign CIP records. Foreign CIP records are identified by the national library of that country or region at the top of the record as: British Library cataloguing in publication data, National Library of Australia cataloging in publication data, etc.
The LCCN takes on different looks based on whether it is printed on the item or keyed into a new bib record. All forms indicate the same information.
For LCCNs assigned prior to 2001, the system prefers the machine readable form of an 8 digit number with zero's inserted in place of the hyphen to fill in for missing digits when fewer than eight are present: 73-33725 has seven digits so one zero is inserted in place of the hyphen:
Keying into a bib record: [space][space]73033725
For LCCNs assigned after 2000, all four digits of the year being indicated in the LC number are included, so a 10 digit number with zero's inserted in place of the hyphen to fill in for missing digits when fewer than ten are present should be entered: 2001-87428 has nine digits so one zero is inserted in place of the hyphen:
Keying into a bib record: [space][space]2001087428
Both indicators are blank.
|a LCCN (Not repeatable)
|z Invalid LCCN (Repeatable)
The LCCN may include any or none of the elements listed below.
The prefix consists of three or fewer alphabetic characters. Enter the prefix into The Cat in lowercase letters and without a space between the letters and the LCCN.
The suffix consists of uppercase alphabetic characters and occurs after the LCCN preceded by a slash ( / ) but no space.
More than one suffix may be present for a single number. Separate each suffix from the one before it by a slash ( / ) but no space.
The revision date indicates how many times and the latest date that the bibliographic information has been updated. It consists of:
- " r ",
- the last two digits of the date of revision,
- the number of times the record has been revised when applicable.
Most commonly a revision date appears alone, without indication of number of revisions.
(Revised once in 1992)
Precede the revision date by a double slash ( // ) when it follows the LCCN.
(Rev. 1965 for the second time.)
Precede the revision date by a slash ( / ) when it follows a suffix
This subfield contains a canceled LCCN or an LCCN incorrectly assigned to the item described in the record (e.g., an incorrect number printed on a book or used in advertisements). The input rules for |z are the same as those for |a described above. Subfield |z is almost never used in MLP records. An invalid LCCN is usually identified as such during full level processing when more information from copy, etc. is available to make this determination.