MARC overview
See also: Bibliographic Formats and Standards - OCLC
What is MARC?
A MARC record is a MAchine–Readable Cataloging record. “Machine–readable” means that a computer can read and interpret the data in a cataloging record. A cataloging record is a bibliographic record, or the information traditionally shown on a catalog card. The record includes: 1) a description of the item, 2) main entry and added entries, 3) subject headings, and 4) the classification or call number. (MARC records often contain a lot of additional information)
Description: We follow the rules in Anglo-American Cataloguing Rules, 2nd ed., 2002 revision (AACR2) and RDA (Resource Description and Access) to compose the bibliographic description of a library item. This “description” was shown in the paragraph sections of a card. It includes the title, statement of responsibility, edition, material specific details, publication information, physical description, series, notes, and standard numbers.
Main entry and added entries: AACR2 and RDA both contain rules for determining controlled vocabulary “access points” to the record (usually referred to as the “main entry” and “other added entries”), and the form these access points should take. Access points are the retrieval points in the library catalog where patrons should be able to look up the item.
Subject headings (subject added entries): We primarily use the Library of Congress Subject Headings (LCSH), or some other list of standard subject headings to select the subjects under which the item will be listed. Use of an approved list is important for consistency, to ensure that all items on a particular subject are found under the same heading and therefore in the same place in the catalog.
Call number: We primarily use Library of Congress or the Dewey Decimal classification systems to select the call number for an item. The purpose of the call number is to place items on the same subject together on the same shelf in the library. Most items are sub-arranged alphabetically by author. The second part of a call number usually represents the author's last name or the first word of a title, which facilitates this sub-arrangement.
Basic MARC Structure
Example of a bibliographic record for a book (in Sierra):