Library of Congress >> MARC >> Bibliographic >> Introduction
MARC 21 Bibliographic
The five MARC 21 communication formats, MARC 21 Format for Bibliographic Data, MARC 21 Format for Authority Data, MARC 21 Format for Holdings Data, MARC 21 Format for Classification Data, and MARC 21 Format for Community Information, are widely used standards for the representation and exchange of bibliographic, authority, holdings, classification, and community information data in machine-readable form.
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 international standard Format for Information Exchange (ISO 2709) and its American counterpart, Bibliographic Information Interchange (ANSI/NISO Z39.2). The content designation--the codes and conventions established explicitly to identify and further characterize the data elements within a record and to support the manipulation of that data--is 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. Examples are the International Standard Bibliographic Description (ISBD), Anglo-American Cataloguing Rules, Library of Congress Subject Headings (LCSH), or other cataloging rules, subject thesauri, and classification schedules used by the organization that creates a record. The content of certain coded data elements is defined in the MARC formats (e.g., the Leader, field 007, field 008).
The MARC 21 Format for Bibliographic Data: Including Guidelines for Content Designation defines the codes and conventions (tags, indicators, subfield codes, and coded values that identify the data elements in MARC bibliographic records. This document is intended for the use of personnel involved in the creation and maintenance of bibliographic records, as well as those involved in the design and maintenance of systems for communication and processing of bibliographic records. This documentation is also available online, including a concise version and a simple field list at: www.loc.gov/marc/.
SCOPE OF THE BIBLIOGRAPHIC FORMAT
MARC 21 Format for Bibliographic Data is designed to be a carrier for bibliographic information about printed and manuscript textual materials, computer files, maps, music, continuing resources, visual materials, and mixed materials. Bibliographic data commonly includes titles, names, subjects, notes, publication data, and information about the physical description of an item. The bibliographic format contains data elements for the following types of material:
- Books (BK) - used for printed, electronic, manuscript, and microform textual material that is monographic in nature.
- Continuing resources (CR) - used for printed, electronic, manuscript, and microform textual material that is issued in parts with a recurring pattern of publication (e.g., periodicals, newspapers, yearbooks). (NOTE: Prior to 2002, Continuing resources (CR) were referred to as Serials (SE)).
- Computer files (CF) - used for computer software, numeric data, computer-oriented multimedia, online systems or services. Other classes of electronic resources are coded for their most significant aspect. Material may be monographic or serial in nature.
- Maps (MP) - used for all types of printed, electronic, manuscript, and microform cartographic materials, including atlases, sheet maps, and globes. Material may be monographic or serial in nature.
- Music (MU) - used for printed, electronic, manuscript, and microform music, as well as musical sound recordings, and non-musical sound recordings. Material may be monographic or serial in nature.
- Visual materials (VM) - used for projected media, non-projected media, two-dimensional graphics, three-dimensional artifacts or naturally occurring objects, and kits. Material may be monographic or serial in nature.
- Mixed materials (MX) - used primarily for archival and manuscript collections of a mixture of forms of material. Material may be monographic or serial in nature. (NOTE: Prior to 1994, Mixed materials (MX) were referred to as Archival and manuscript material (AM)).
Kinds of Bibliographic Records
MARC bibliographic records are distinguished from all other types of MARC records by specific codes in Leader/06 (Type of record) which identifies the following bibliographic record types.
|Language material||Nonmusical sound recording|
|Manuscript language material||Musical sound recording|
|Computer file||Projected medium|
|Cartographic material||Two-dimensional nonprojectable graphic|
|Manuscript cartographic material||Three-dimensional artifact or natural objects|
|Manuscript music||Mixed material|
Microforms, whether original or reproductions, are not identified as a special type of record. The microform aspect is secondary to the type of material to which the original item belongs (e.g., book). The same is true for Computer Files in that the computer file aspect is secondary; however, certain categories of electronic resources are coded as Computer Files.
COMPONENTS OF BIBLIOGRAPHIC RECORDS
Description of Record Parts
A MARC bibliographic record consists of three main components: the Leader, the Directory, and the variable fields. The following information summarizes the structure of a separate MARC record. More detail is provided in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media.
- Leader - Data elements that primarily provide information for the processing of the record. The data elements contain numbers or coded values and are identified by relative character position. The Leader is fixed in length at 24 character positions and is the first field of a MARC record.
- Directory - 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 the field 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 bibliographic 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 last variable field in a record ends with both a field terminator and a record terminator (ASCII 1D hex). There are two types of variable fields.
- Variable control fields - The 00X fields. These fields are identified by a field tag in the Directory but they contain neither indicator positions nor subfield codes. The variable control fields are structurally different from the variable data fields. 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 remaining variable fields defined in the format. In addition to being identified by a field tag in the Directory, variable data fields contain two indicator positions stored at the beginning of each field and a two-character subfield code preceding each data element within the field.
- The variable data fields are grouped into blocks according to the first character of the tag, which with some exceptions identifies the function of the data within the record. The type of information in the field is identified by the remainder of the tag.
|0XX||Control information, identification and classification numbers, etc.|
|2XX||Titles and title paragraph (title, edition, imprint)|
|3XX||Physical description, etc.|
|6XX||Subject access fields|
|7XX||Added entries other than subject or series; linking fields|
|8XX||Series added entries, holdings, etc.|
|9XX||Reserved for local implementation|
Within the 1XX, 4XX, 6XX, 7XX and 8XX blocks, certain parallels of content designation are usually preserved. The following meanings, with some exceptions, are given to the final two characters of the tag of fields:
|X00||Personal names||X40||Bibliographic titles|
|X10||Corporate names||X50||Topical terms|
|X11||Meeting names||X51||Geographic names|
Within variable data fields, the following two kinds of content designation are used:
- Indicator positions - The first two character positions in the variable data fields 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 a numeric character. A blank (ASCII SPACE), represented in this document as a #, 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 distinguish the data elements within a field which require separate manipulation. A subfield code consists of a delimiter (ASCII 1F hex), represented in this document as a $, followed by a data element identifier. Data element identifiers may be a lowercase alphabetic or a numeric character. Subfield codes are defined independently for each field; however, parallel meanings are preserved whenever possible (e.g., in the 100, 400, and 600 Personal Name fields). Subfield codes are defined for purposes of identification, not arrangement. The order of subfields is generally specified by standards for the data content, such as cataloging rules.
Multiscript Bibliographic Records
A MARC bibliographic 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. General models for multiscript data are described in Appendix D along with several examples.
Field and Subfield Repeatability
Theoretically, all fields and subfields may be repeated. The nature of the data, however, often precludes repetition. For example, a bibliographic record may contain only one 1XX main entry field; a 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). The repeatability or non-repeatability of each field and subfield is specified in the format.
Fields in the record may be specially linked using a generally-applicable field linking technique. The technique relies upon the syntax of data in subfield $8 (Field link and sequence number) to identify the linked fields. The structure and syntax for the field link and sequence number subfield are described in Appendix A.
Fill Character and Related Values
A fill character (ASCII 7C hex), represented in this document as a vertical bar (|), may be used in bibliographic records in fields 006, 007, and 008, and subfield $7 of field 533 (Reproduction note) and the linking entry fields (760-787). A fill character may not be used in the leader, or in 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. The presence of a fill character in a bibliographic record indicates that the format specifies a code to be used but the creator of the record has decided not to attempt to supply a code.
Code u (Unknown or unspecified) when it is defined indicates 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) is defined in many coded positions to indicate that the characteristic defined by the position is not applicable to a specific type of item or kind of record.
A display constant is a term, phrase, spacing, or punctuation convention that may be system generated in order to make a visual presentation of data in a record more meaningful to a user. In the bibliographic format certain field tags (e.g., field 770, Supplement/Special Issue Entry), indicators (e.g. field 511 Indicator 1, Display constant controller), and subfield codes (e.g., the subject subdivision subfields $x, $y, and $z in a subject added entry), may be used to generate specific terms, phrases, and/or spacing or punctuation conventions for the display of a record. The use of display constants is determined by each organization or system. Examples of display constants are provided under Input Conventions in the field descriptions.
Record Content Responsibility
The MARC 21 Format for Bibliographic Data serves as a vehicle for bibliographic data of all types from any organization. In general, the responsibility for the data content, content designation, and transcription of bibliographic information within a 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 a controlled-list data element.
In unmodified records, the organization identified as the original cataloging source in 008/39 and/or 040 $a is responsible for the content of the record. The organization identified as the transcribing agency in field 040 $c is responsible for the content designation and transcription of the data.
In modified records, the organizations identified in 040 $a and $d (Modifying agency) are collectively responsible for the 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). 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.
Record Level Requirements
User groups may have full level and minimal level record requirements to promote consistency across cataloging agencies. These should be widely publicized for all possible interchange partners to be aware.
ORGANIZATION OF THIS DOCUMENT
MARC 21 Format for Bibliographic Data consists of a Summary Statement of Content Designators followed by a detailed presentation of each content designator. Following the descriptions of the Leader and the Directory, the detailed presentations for each variable field are arranged in field tag order.
Appendixes to this document provide information about several control subfields (Appendix A), full level record examples (Appendix B), minimal level record examples (Appendix C), multiscript record examples (Appendix D), an alphabetical listing of ambiguous headings with suggested tagging (Appendix E), a multilingual list of initial definite and indefinite articles (Appendix F), lists of changes to the format since the last edition or update (Appendix G), a listing of several Canadian and American local fields (Appendix H) and a list of organization code sources (Appendix I).
General Information Sections
To avoid repetition, general information sections are provided for groups of fields with similar characteristics. These general information sections provide instructions for the content designators that are common to each field in the group. The description for each of the fields refers back to the general information section for that group and to any related general information section.
For example, the X00 Personal Name--General Information section is provided for personal name headings. This general information section provides instructions for the content designators that are common to each type of personal heading whether it is used in a 100 main entry field, a 600 subject access field, an 700 added entry field, or a 800 series added entry field. The description for each of the individual fields (i.e., 100, 600, 700, 800) refers back to the X00 general information section.
Components of the Detailed Descriptions
A detailed description may consist of six parts: content designator listing; character position or field definition and scope; guidelines for applying content designators, with examples; input conventions; and content designator history.
The content designator listing area presents
- the name of the content designator
- the repeatability/nonrepeatability code (R or NR)
For the Leader and the variable control fields, the list gives the name of the character position and any defined coded value. For the variable data fields, the list gives the name of the indicator positions and any defined coded values and the name of the subfield codes and any defined coded values. For all variable fields, the repeatability/nonrepeatability code at the field level specifies whether the field may be repeated in a record. For variable data fields, the subfield repeatability code specifies whether the subfield code may be repeated within a field.
The character position or field definition and scope area describes the contents of the character position or field, the appropriateness of its use in specific kinds of bibliographic records, and gives other information, such as field repeatability in particular circumstances, the use of required lists or rules in formulating the data, etc.
The guidelines for applying content designators area describes the content and scope of each coded value, indicator, or subfield code and gives other information, such as appropriateness for use and repeatability in certain circumstances. The coded values and subfield codes in this area are presented in alphabetical/numerical order. Examples showing the use of the content designator are provided immediately following the description. The examples illustrate the application of specific MARC content designation. The data may be fuller or less full than would be used in actual cataloging practice. Most of the examples reflect the application of AACR 2 and ISBD; however, some reflect a generalized MARC application. Other examples illustrate specific points.
The input conventions area provides general guidance for the application of the content designators, and for such things as punctuation, spacing, and the use of display constants. The punctuation used within a field is generally dictated by descriptive cataloging or subject heading system/thesaurus rules. The input conventions clarify MARC punctuation practices especially with respect to final punctuation. In the discussion of punctuation practices, mark of punctuation is a period (.), a question mark (?), an exclamation mark (!), or a hyphen (-).
The content designator history area provides a record of significant content designator changes. The types of changes that are included are:
- newly defined content designators that impact on coding consistency within a file, e.g., the location of a meeting entered under a corporate body was not separately subfield coded in the X10 fields prior to the definition of subfield $c in 1980.
- redefined codes and values, e.g., in X10 fields, both the number and the name of a part/section of a work were contained in subfield $p prior to the redefinition of subfield $p for only the name of a part/section of a work in 1979.
- changes in codes and values for consistency across MARC specifications, e.g., in 008/24-27 for the books specifications, code f (Handbooks) was identified by code h prior to 1979.
- changes in repeatability when it impacts on file consistency, e.g., field 020 was not repeatable prior to 1977; multiple ISBN data were contained in repeatable subfields $a, $b, and $c.
- restructuring, e.g., field 007 (Physical Description Fixed Field) in 1980.
- obsolete content designation, e.g., subfield $b (Number) in the X11 fields when subfield $n was redefined to include meeting numbers in 1979. Obsolete content designation formerly defined in only one format are designated [USMARC only] or [CAN/MARC only]; unmarked items were defined in both formats.
In the MARC formats, a distinction is made between obsolete and deleted content designators. An obsolete content designator is one that may have been used in MARC records and that may continue to appear in records created prior to the date it was made obsolete. Obsolete content designators are not used in new records. An obsolete content designator is recorded in the Content Designator History area. Content designation instructions are provided for retrospective conversion of records having data elements that would have been identified by the obsolete content designator. A deleted content designator is not recorded in the history area and will no longer appear anywhere in the MARC documentation. A content designator that had been reserved in MARC but has not been defined, or one that had been defined but is known with near certainty not to have been used, may be deleted from the format. A deleted content designator is available for redefinition in a format. A deleted content designator is available for redefinition in a format.
Throughout this document, the following typographical conventions are used:
- 0 - The graphic 0 represents the digit zero in tags, fixed-position character positions, indicator positions, and other places numerics are used. This character must be distinguished from an uppercase letter O in examples or text.
- # - The graphic symbol # is used for a blank in coded fields and in other special situations where the existence of the character blank might be ambiguous. (In most textual examples, the blank is represented in the conventional way, by the absence of a character.)
- $ - The graphic symbol $ is used for the delimiter portion of a subfield code. Within the text, subfield codes are referred to as subfield $a, for example.
- / - Specific character positions of the Leader, Directory, field 007, field 008 are expressed using a slash and the number of the character position, e.g., Leader/06, 007/00, 008/12.
- 1 - The graphic 1 represents the digit one (hex 31). This character must be distinguished from a lowercase roman alphabet letter l (hex 6C) and uppercase alphabetic letter I (hex 4C) in examples or text.
- | - The graphic | represents a fill character in MARC examples. When this mark appears in the left margin, it indicates areas of the text of this document where changes have been made.
STANDARDS AND OTHER DOCUMENTS RELATED TO THIS FORMAT
The MARC 21 Format for Bibliographic Data should be used with the following standards and related documentation. When a standard is applicable to data in specific fields of the format, the fields are given in brackets following the citation.
National and International Standards:
ISO publications may be obtained from the International Organization for Standardization (ISO) and their agents; and ANSI/NISO Z39 publications may be obtained from the National Information Standards Organization (NISO).
- Format for Information Exchange (ISO 2709) and Bibliographic Information Interchange (ANSI/NISO Z39.2)
- Code for the Representation of Names of Countries and their Subdivisions: Part 2, Country subdivision code (ISO 3166-2)
- International Standard Book Numbering (ISBN) (ISO 2108)
- International Standard Music Number (ISMN) (ISO 10957)
- International Standard Recording Code (ISRC) (ISO 3901)
- International Standard Serial Number (ISSN) (ISO 3297) (ANSI/NISO Z39.9)
- Representations of Dates and Times (ISO 8601)
- Serial Item and Contribution Identifier (SICI) (ANSI/NISO Z39.56)
- International Standard Technical Report Number (ISRN) (ISO 10444) and Standard Technical Report Number and Description (ANSI/NISO Z39.23)
These publications are available from the Library of Congress, Cataloging Distribution Service, Washington, DC 20541, USA (Worldwide distribution). Where indicated these publications are available on the Internet.
This document supersedes the most recent editions of the USMARC Format for Bibliographic Data and the Canadian MARC Communication Format for Bibliographic Data. With alignment of these formats in 1997, a single edition of the format could be issued.
MARC 21 supersedes the 1994 edition of USMARC Format for Bibliographic Data: Including Guidelines for Content Designation and updates No. 1 (March 1995), No. 2 (March 1996), and No. 3 (July 1997) to that edition. With Update No.3 the USMARC and CAN/MARC formats were identical format specifications. The 1994 edition superseded the 1988 edition of the format and its four updates published between 1988 and 1991. The 1988 edition incorporated the base text of the 1980 edition published under the title MARC Formats for Bibliographic Data (MFBD) and the 15 updates to that edition published between 1980 and 1987. The 1980 edition was a compilation of separate MARC format documents developed for different types of material and published between 1969 and 1977.
MARC 21 supersedes the 1994 edition of Canadian MARC Communication Format for Bibliographic Data and its six updates published between 1994 and 1998. Update number six contained the changes to CAN/MARC required to align with USMARC. With this update, the specifications contained in the CAN/MARC and USMARC formats were identical. The 1994 edition superseded the 1988 edition and its seven updates issued between 1988 and 1991. The 1988 edition was produced by amalgamating separately issued CAN/MARC formats for monographs and serials.
The MARC 21 Format for Bibliographic Data is prepared by the Network Development and MARC Standards Office, Library of Congress, in cooperation with Content Management Division, Library and Archives Canada (previously National Library of Canada) and Bibliographic Standards and Systems, British Library. Please direct any questions related to the content of this document to one of the following:
Network Development and MARC Standards Office
Library of Congress
101 Independence Avenue, S.E.
Washington, DC 20540-4402, USA
Email: [email protected]
Library and Archives Canada
395 Wellington St.
Ottawa, Ontario K1A 0N4, Canada
Email: [email protected]
The British Library
Boston Spa, Wetherby
West Yorkshire LS23 7BQ, United Kingdom
Fax: +44 (0) 1937 546586
Email: [email protected]
The MARC 21 Format for Bibliographic Data is organized on a field-by-field basis with each field separately paged to facilitate the updating of fields. Periodic updates of new and replacement pages for the base text and cumulated versions of the base text will be available from the Cataloging Distribution Service, Library of Congress, Washington, DC 20541-5017, USA (Worldwide distribution) and available in Canada from Publishing and Depository Services, Public Works and Government Services Canada (PWGSC), Ottawa, Ontario K1A 0S5, Canada (Canadian distribution). Their availability will be announced on the Library of Congress MARC website, the Library and Archives Canada MARC website, on listservs, and through press releases to the library press and to those who purchase the initial base volume. Updates are also available on standing order from the Library of Congress and the Canadian Government Publishing-PWGSC. This publication and all updates are supplied to all purchasers of the Library of Congress MARC Distribution Service files of bibliographic records as part of their MARC record subscription.
ISO 12615:2004 applies to the recording, storing and exchange of information on bibliographic sources for terminological work and terminography. It specifies the data elements to be included in bibliographic references for terminology work. These references can be used as data categories in computer applications in terminology or in presenting bibliographies and lists of references accompanying other textual matter, and citations in journal articles. ISO 12615:2004 does not apply to bibliographic descriptions that record and identify documents and are used by librarians, bibliographers and indexers.
ISO 12615:2004 also describes source identifiers for different types of bibliographical references and their use. It indicates how the data elements from the bibliographic reference can be reflected in a source identifier, and how its constituent parts can be assembled to provide a unique identifier.
ISO 12615:2004 will facilitate the following:
- identifying, tracing and validating terminological data and other language resources;
- cross-referencing to documents containing terminological data;
- data flow management in networking and other cooperative work in terminology documentation and terminography;
- exchange of terminological data;
- preparation of technical documents;
- carrying out of individual projects of terminology and terminography.
Current status : Published
Publication date : 2004-12
Edition : 1
Number of pages : 26
ISO/TC 37/SC 2
Terminology workflow and language coding
- ICS :
Terminology (principles and coordination)