Intended to be used for comparative purposes and in the design of generalized computer programs for systems using the MARC formats for bibliographic records, this publication contains a listing in tabular form of the content designators used in the various MARC formats. Content designators are listed under Leader, Control Fields, and Variable Fields, and the formats in which they are used in MARC records are indicated: books, films, manuscripts, maps, music, serials, and in process materials. For a complete description of the content designators used in each format the reader is advised to consult the individual formats published by the Library of Congress. (Author/AP)