The Library of Congress (LC) Guidelines for MARC 21 authority records are intended to be used in conjunction with the MARC 21 Format for Authority Data (Washington, D.C.: Library of Congress, Cataloging Distribution Service, 1999- ).  They were prepared by the Cataloging Policy and Support Office and the Cooperative Cataloging Team in the Regional and Cooperative Cataloging Division and are based on previous editions compiled by the Network Development and MARC Standards Office.

Scope of LC Guidelines:

The LC Guidelines present information relating to two areas of usage in authority records:

usage pertaining to records contributed to the authority files by participants in the Name Authority Cooperative (NACO) or Subject Authority Cooperative (SACO) programs; and

usage pertaining to authority records created and updated by LC.

Records include name, series, and subject authority records.

In April 2017, the LC Guidelines were expanded to include fields and subfields for which no implementation decision has been made yet.  These fields and subfields contain instructions not to use them with the additional text "implementation decision not yet made."  They will be updated to reflect implementation decisions when appropriate.

The guidelines were developed from various internal and published documents, including the MARC 21 Format for Authority Data 1999 base text with updates, the most recent editions of the NACO Participants' Manual, and the SACO Participants' Manual.

Direction for use of LC Guidelines:

The LC Guidelines for authority records should be used by LC catalogers and institutions participating in NACO or SACO and creating authority records to be added to the authority files.  The guidelines may also be used by institutions that need or want to know special LC practice in authority records.  As already mentioned, these guidelines are intended to be used in conjunction with the MARC 21 Format for Authority Data.  Data requirements that are not specific to NACO or SACO and/or LC are presented only in the main text of the authorities format.

NACO/SACO participants and LC staff creating authority records must also apply the appropriate procedures presented in various LC cataloging documents (e.g., the Descriptive Cataloging Manual (DCM), and the Subject Headings Manual (SHM)).  Cooperating institutions may also refer to the NACO Participants' Manual and the SACO Participants' Manual.

Organization of LC Guidelines:

Each guidelines topic is marked at the top with the title of the MARC 21 format section (usually a three-digit field tag) to which it applies.

NACO usage and SACO usage sections are given first, with a list of data elements receiving special treatment and explanatory text where appropriate.  When there is no special NACO and/or SACO usage, any data requirements detailed in the main text of the Authority format are still applicable.

LC usage follows NACO/SACO usage sections.  The LC usage section is also divided into subsections on Name/Series usage, and Subject usage, as appropriate.  Some LC usage may be more restrictive than that prescribed for NACO and SACO participants.  NACO and SACO participants may not be restricted necessarily from using specific data elements even though LC does not use them.  These differences are noted when they occur.

Instructions for genre/form terms and medium of performance terms fields and subfields are given in the SACO and LC Subjects usage sections.

Note: As of June 1, 2006, LC does not create or update SARs.

This Help:

There are two ways to access the LC Guidelines in this Help:

from the specific field or character position to which the guidelines apply

from the LC Guidelines listing of affected fields and character positions

To return:

LC Guidelines

MARC 21 Format for Authority Data:  Contents