MARC

The MARC 21 Concise Formats are officially published online once a year 
(usually in October through December). It uses red highlights to 
indicate changes made from the previous published edition.

The MARC 21 formats are widely used standards for the representation and 
exchange of authority, bibliographic, classification, community 
information, and holdings data in machine-readable form. They consist of 
a family of five coordinated formats: MARC 21 Format for Authority Data; 
MARC 21 Format for Bibliographic Data; MARC 21 Format for Classification 
Data; MARC 21 Format for Community Information; and MARC 21 Format for 
Holdings Data. Each of these MARC formats is published separately to 
provide detailed field descriptions, guidelines for applying the defined 
content designation (with examples), and identification of conventions 
to be used to insure input consistency. The MARC 21 Concise Formats 
provide in a single publication a quick reference guide to the content 
designators defined in each MARC format. It provides a concise 
description of each field, each character position of the fixed-length 
data element fields, and of the defined indicators in the variable data 
fields. Descriptions of subfield codes and coded values are given only 
when their names may not be sufficiently descriptive. Examples are 
included for each field.



COMPONENTS OF A MARC 21 RECORD
MARC format characteristics that are common to all of the formats are 
described in this general introduction. Information specific only to 
certain record types is given in the introduction to the MARC format to 
which it relates.

A MARC record is composed of three elements: the record structure, the 
content designation, and the data content of the record. The record 
structure is an implementation of the American National Standard for 
Information Interchange (ANSI/NISO Z39.2) and its ISO equivalent ISO 
2709. The content designation--the tags, codes, and conventions 
established explicitly to identify and further characterize the data 
elements within a record and to support the manipulation of that data 
are defined by each of the MARC formats. The content of the data 
elements that comprise a MARC record is usually defined by standards 
outside the formats, such as the International Standard Bibliographic 
Description (ISBD), Anglo-American Cataloguing Rules, 2nd edition (AACR 
2), Library of Congress Subject Headings (LCSH), Holdings Statements 
Summary Level (ISO 10324), American National Standard for Serial 
Holdings Statements (ANSI/NISO Z39.44), Library of Congress 
Classification (LCC), or other conventions used by the organization that 
creates a record. The content of certain coded data elements (e.g., the 
Leader, fields 007 and 008) is defined in the MARC formats themselves.

The MARC record structure consists of three main components: the Leader, 
the Directory, and the Variable Fields. The following information 
summarizes the components of a MARC record. More detail is provided in 
MARC 21 Specifications for Record Structure, Character Sets, and 
Exchange Media.


Leader
Contains data elements that provide information for the processing of 
the record. The data elements contain numbers or coded values and are 
identified by a relative character position. The Leader is fixed in 
length at 24 character positions and is the first field in all MARC records.

Directory
Contains a series of entries that contain the tag, length, and starting 
location of each variable field within a record. Each entry is 12 
character positions in length. Directory entries for variable control 
fields appear first, sequenced by tag in increasing numerical order. 
Entries for variable data fields follow, arranged in ascending order 
according to the first character of the tag. The stored sequence of the 
variable data fields in a record does not necessarily correspond to the 
order of the corresponding Directory entries. Duplicate tags are 
distinguished only by the location of the respective fields within the 
record. The Directory ends with a field terminator character (ASCII 1E hex).

Variable fields
The data in a MARC 21 record is organized into variable fields, each 
identified by a three-character numeric tag that is stored in the 
Directory entry for the field. Each field ends with a field terminator 
character. The MARC record ends with a record terminator (ASCII 1D hex). 
There are two types of variable fields:

Variable control fields
The tagged 00X fields. The variable control fields are structurally 
different from the variable data fields. These fields contain neither 
indicator positions nor subfield codes. They may contain either a single 
data element or a series of fixed-length data elements identified by 
relative character position.

Variable data fields
The tagged 01X-8XX fields.
Within variable data fields, the following two kinds of content 
designation are used:

Indicator positions
The first two character positions at the beginning of each variable data 
field that contain values which interpret or supplement the data found 
in the field. Indicator values are interpreted independently, that is, 
meaning is not ascribed to the two indicators taken together. Indicator 
values may be a lowercase alphabetic or numeric character. A blank 
(ASCII 20 hex), represented in this document as a pound symbol (#), is 
used in an undefined indicator position. In a defined indicator 
position, a blank may be assigned a meaning, or may mean no information 
provided.

Subfield codes
Two characters that precede each data element within a field that 
requires separate manipulation. A subfield code consists of a delimiter 
(hex 1F), represented in this document as a dollar sign ($), followed by 
a data element identifier. Data element identifiers are lowercase 
alphabetic or numeric characters. Subfield codes are defined 
independently for each field; however, parallel meanings are preserved 
where possible. Subfield codes are defined for purposes of 
identification. The order of subfields is generally specified by 
standards for the data content, such as the cataloging rules.
MULTISCRIPT RECORDS
A MARC 21 record may contain data in multiple scripts. One script may be 
considered the primary script of the data content of the record, even 
though other scripts are also used for data content. (Note: ASCII is 
used for the structure elements of the record, with most coded data also 
specified within the ASCII range of characters.) Graphic models for 
multiscript data are described in the "Multiscript Records" sections, 
located at the end of each format.

FIELD AND SUBFIELD REPEATABILITY
Theoretically, all fields and subfields may be repeated. The nature of 
the data, however, often precludes repetition. For example, a record may 
contain only one 1XX field; a bibliographic field 100 may contain only 
one subfield $a (Personal name) but may contain more than one subfield 
$c (Titles and other words associated with a name). Field and subfield 
repeatability/nonrepeatability is indicated by (R) or (NR) following 
each field and subfield in each MARC 21 format.

FILL CHARACTER AND RELATED VALUES
A fill character (ASCII 7C hex), represented in this document as a 
vertical bar (|), may be used in a record when the format specifies a 
code to be used but the creator of the record decides not to attempt to 
supply a code. A fill character may not be used in any character 
position of the leader or tags, indicators, or subfield codes. The use 
of the fill character in records contributed to a national database may 
also be dependent upon the national level requirements specified for 
each data element.

Code u (Unknown or unspecified), when it is defined, is used to indicate 
that the creator of the record attempted to supply a code but was unable 
to determine what the appropriate code should be.

Code n (Not applicable), when it is defined, is used to indicate that 
the characteristic defined by the position is not applicable to a 
specific type of item or kind of record.

DISPLAY CONSTANTS
A display constant is a term, phrase, and/or spacing or punctuation 
convention that may be system generated to make a visual presentation of 
data in a record more meaningful to a user. The display text is not 
carried in the record but an indication for it, based on tags, 
indicators, subfield codes, or coded values, is. Suggested display 
constants and display examples are provided in each MARC 21 format. The 
use and display of these constants is determined by each organization or 
system.

Record Content Responsibility
In general, the responsibility for the data content, content 
designation, and transcription of data within a MARC 21 record may be 
determined by examination of the field indicated in the responsible 
parties section below. The data content of certain data elements, 
however, is restricted when the element is an agency-assigned or an 
authoritative-agency data element.
Responsible Parties
In unmodified records, the organization identified as the original 
cataloging source in 008/39 and/or 040 $c (Transcribing agency) is 
responsible for the data content of the record. The organizations 
identified as the transcribing agency in field 040 is responsible for 
the content designation and transcription of the data.

In modified records, organizations identified in field 040 $a (Original 
cataloging agency) and $d (Modifying agency) are collectively 
responsible for the data content of the record. Organizations identified 
as transcribing or modifying agencies in field 040 $c and $d are 
collectively responsible for the content designation and transcription 
of the data.
Agency-Assigned Data Elements
An agency-assigned data element is one whose content is determined by a 
designated agency and is the responsibility of that agency, e.g., field 
222 (Key Title) which is the responsibility of an ISSN Center. While it 
is usually input by the designated agency, it may be transcribed by 
another organization.
Controlled-List Data Elements
Certain data elements contain data from controlled lists maintained by 
designated agencies, e.g., the MARC Code List for Geographic Areas in 
field 043 (Geographic Area Code) of the bibliographic format.

These elements are indicated at the field or subfield level in MARC 21 
and only values from the designated lists may be used. If a change or 
addition is desirable for a list, the maintenance agency for the list 
should be consulted.
OBSOLETE CONTENT DESIGNATORS
Obsolete content designators are not included in this document. A Web 
listing is available under the MARC Field Lists at: www.loc.gov/marc/. 
An obsolete content designator is not used in new records. It may appear 
in records that were created prior to the time that it was made obsolete.

TYPOGRAPHICAL CONVENTIONS
Throughout this document, the following typographical conventions are used:

0 - The graphic 0 represents the digit zero in tags, fixed-position 
character position citations, and indicator positions. This character is 
distinct from an uppercase letter O used in examples or text.


# - The graphic symbol # is used for a blank (hex 20) in coded fields 
and in other special situations where the existence of the character 
blank might be ambiguous.


$ - The graphic symbol $ is used for the delimiter (ASCII 1F hex) 
portion of a subfield code. Within the text, subfield codes are referred 
to as subfield $a, for example.


/ - Specific character positions of fixed-length data elements, such as 
those in the Leader, Directory, and field 008, are expressed using a 
slash and the number of the character position, e.g., Leader/06.


1 - The graphic 1 represents the digit one (hex 31). This character must 
be distinguished from a lowercase roman alphabet letter l (el) (hex 6C) 
and the uppercase alphabetic letter I (eye) (hex 49) in examples or text.


| - The graphic | represents a fill character (hex 7C).
ACRONYMS AND INITIALISMS
The acronyms and initialisms that are used in the MARC 21 Concise 
Formats are only briefly defined here. Detailed explanations may be 
found in the relevant documentation named in the brief definition, the 
MARC 21 Specifications for Record Structure, Character Sets, and 
Exchange Media, and/or one of the five MARC 21 communications format 
publications.

AACR 2 - Anglo-American Cataloguing Rules, 2nd edition, (2002 revision); 
and AACR 2 based cataloging manuals
ANSI - American National Standards Institute
DDC - Dewey Decimal Classification
ISBD - International Standard Bibliographic Description
ISBN - International Standard Book Number formulated according to Book 
numbering (ANSI/NISO Z39.21)
ISO - International Organization for Standardization
ISRC - International Standard Recording Code
ISSN - International Standard Serial Number formulated according to 
International Standard Serial Numbering (ANSI/NISO Z39.9)
LCC - Library of Congress Classification
LCSH - Library of Congress Subject Headings
MeSH - Medical Subject Headings
NISO - National Information Standards Organization
NR - Not repeatable
R - Repeatable
STRN - Standard Technical Report Number (STRN), Format and Creation 
(ANSI/NISO Z39.23)
DOCUMENTATION MAINTENANCE
The MARC 21 Concise Formats are prepared by the Network Development and 
MARC Standards Office. Direct any questions related to the content of 
this document to the Library of Congress, Network Development and MARC 
Standards Office, 101 Independence Ave., S.E., Washington, DC 20540-4402 
(FAX +1-202-707-0115). Correspondence may also be sent to the office 
email account at: ndmso@loc.gov.

The following list gives the MARC 21 format documents whose data 
elements have been incorporated into this edition of the MARC 21 Concise 
Formats :

MARC 21 Format for Authority Data (1999 base text) and Update No. 1 
(October 2000); Update No. 2 (October 2001); Update No. 3 (October 
2002); Update No. 4 (October 2003); Update No. 5 (October 2004); Update 
No. 6 (October 2005); Update No. 7 (October 2006)

MARC 21 Format for Bibliographic Data (1999 base text) and Update No. 1 
(October 2000); Update No. 2 (October 2001); Update No. 3 (October 
2002); Update No. 4 (October 2003); Update No. 5 (October 2004); Update 
No. 6 (October 2005); Update No. 7 (October 2006)

MARC 21 Format for Classification Data (2000 base text) and Update No. 1 
(October 2000); Update No. 2 (October 2001); Update No. 3 (October 
2002); Update No. 4 (October 2003); Update No. 5 (October 2004); Update 
No. 6 (October 2005); Update No. 7 (October 2006)

MARC 21 Format for Community Information (2000 base text) and Update No. 
1 (October 2000); Update No. 2 (October 2001); Update No. 3 (October 
2002); Update No. 4 (October 2003); Update No. 5 (October 2004); Update 
No. 7 (October 2006)


MARC 21 Format for Holdings Data (2000 base text) and Update No. 1 
(October 2000); Update No. 2 (October 2001); Update No. 3 (October 
2002); Update No. 4 (October 2003); Update No. 5 (October 2004); Update 
No. 6 (October 2005); Update No. 7 (October 2006)