School of Information Management & Systems. Spring 2002.
245 Organization of Information in Collections. Michael Buckland.

MARC Remarks. Revised March 18, 2002.
Sources: Taylor, Organization Chap 4;   Library of Congress MARC Website and Tutorial.
    MARC (MAchine Readable Cataloging) is a generic name for many individual standards for computer-to-computer communication of catalog-related records. National (USMARC Information Interchange Format ANSI Z39.2), international (Format for Information Exchange ISO 2709), and foreign, e.g., CANMARC; UKMARC,... US libraries have now adopted MARC21 a harmonized version of USMARC and CANMARC.
    The MARC format was developed for Bibliographic data (a description of a book or other informative thing, usually a catalog record); later versions were created for Authority data (To record the authorized form of a name or title when used as a heading); Classification (record for a classification number); Community Information records; and Holdings data (noting precisely which parts of, e.g., a serial, are held).
    Different MARC formats for records describing different types of material: BK Books; AM Archival & Manuscripts; CF Computer File; MP Maps; MU Music; VM Visual Material; SE SErials, periodicals, newspapers have been consolidated into MARC21.
    Rules for creating content are external to MARC, e.g. Anglo-American Cataloging Rules (AACR2R) and the International Standardized Bibliographic Description (ISBD).
    MARC records have four elements: Leader; Record Directory;
Control Fields (including "the Fixed Field" (008) field): containing relatively simple alphanumeric codes for date, language, biography, etc. See top three lines of MELVYL CAT "MARC" display;
Tagged (variable) fields (010-9XX, where (9XX are reserved for local use). Variable data fields of variable length, for catalog data such as title, author names, subject headings, notes, etc. Variable data fields may be absent, present once, present multiple times. So may each subfields.
    Variable data fields have four elements: 1. A tag indentifies field, e.g. tag 245 signifies "title and statement of responsibility"; 2. Two indicators may signal something about the field, e.g. starts with 4 non-filing characters; 3. Subfields preceded by subfield indicators e.g. "$" followed by a lower case letter, e.g. In field 260 Imprint, "$e" indicates Place of manufacture. 4. Content.
    Example: 245 14 $aThe emperor's new clothes / $c by Hans Christian Andersen.
where "1" = make a title added entry and "4" = disregard first 4 characters when filing.
    Variable data fields are classified into ten blocks: 0XX Control info; 1XX Main entries; 2XX Titles and title paragraph; 3XX Physical description; 4XX Series statements; 5XX Notes; 6XX Subject access; 7XX Added entries (not subject or series); linking fields; 8XX Series added entries; 9XX Reserved for local info.
    Parallel treatment within blocks 1XX, 2XX, 6XX, 7XX and 8XX (with exceptions): X00 Personal names; X10 Corporate names; X11 Meeting names; X30 Uniform titles; X40 Bibliographic titles; X50 Topical terms; X51 Geographic names.
    Fields subject to authority control: 1XX Main entries; 4XX Series statements; 6XX Subject headings; 7XX Other added entries; 8XX Series added entries.
    Four kinds of completeness of data entry: M-Mandatory: Must supply; A-Mandatory if applicable; O-Optional; U-Unused, i.e. Don't use!
    b with superimposed / denotes a blank space.
    Most important fields are: 010 Library of Congress Control Number (LCCN)
020 International Standard Book Number (ISBN)
100 personal name main entry (author)
245 title (which incl. the title, other title information, and the statement of responsibility)
250 the edition
260 publication information ("Imprint")
300 physical description ("collation")
440 series statement/added entry
520 annotation or summary note
650 topical subject heading
700 personal name added entry (joint author, editor, or illustrator)