Library of Congress

The Dewey Program at the Library of Congress

The Library of Congress > Acquisitions, Cataloging > Dewey > LC Dewey Practices
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The Library of Congress Dewey Program applies unabridged Dewey classification to all the works it classifies, with a few exceptions.  Where possible, the LC Dewey Program utilizes tools to make DDC classification as efficient as possible. Please contact [email protected] for more information.

  • Update to DDC (082 MARC field)
    The MARC Advisory Committee recently approved an update to the format of the MARC 082 field in bibliographic records. The LC Dewey Program will implement the new format on October 1, 2021.
  • Alternate DDC Notation in LC Bibliographic Records
    Libraries using cataloging data provided by the Library of Congress will notice that sometimes there is non-numeric notation in the DDC (082 MARC) field.  Examples are included that explain the practices of the Dewey Program with respect to alternate DDC notation.
  • AutoDewey
    A cataloging ILS application designed to take advantage of those areas where Library of Congress Classification (LCC) and Dewey Decimal Classification (DDC) are similar enough that semi-automatic assignment of DDC number based on LCC number is useful.   AutoDewey is designed for easy use by the same catalogers who assign LCC numbers.
  • Copy Cataloging
    The Dewey Program increasingly depends on copy cataloging work flows to supplement its production. Dewey Program classifiers aim to provide standard, complete Dewey numbers with segmentation marks; however, the Library of Congress also avails itself of Dewey numbers supplied by other institutions.

ISSN and Dewey

In conjunction with the assignment of the ISSN (International Standard Serial Number) to U.S. serials and integrating resources cataloged by the Library of Congress or requested by ISSN users, a Dewey classification number will usually be assigned.  These Dewey numbers may consist of a full classification number assigned by another institution as found on copy, a pre-built number from WebDewey, or an abridged Dewey number found in WebDewey.  The Dewey classification  number for an ISSN assignment will have a minimum of three digits.