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The Library of Congress has several million MARC bibliographic records called PREMARC records. These are older bibliographic records that were retrospectively converted, for the most part, from the Library’s card shelf lists by the Carrollton Press, which marketed the records originally under the name “REMARC.” In most cases these records contain only a subset of the data elements from the source cards. In addition, they include various conditions requiring maintenance to make them more viable for use both internally and externally. As a means of executing this enhancement/maintenance process, the Library between 1993-1997 contracted with OCLC for “replacement” records. Under this contract copies of certain PREMARC records for books were sent to OCLC for replacement by counterpart matching records in the OCLC database--hence the term “OCLC replacement records.” Approximately 1.2 million OCLC matching records were returned to LC and replaced most of the data elements within the original PREMARC records. (The call number in the original PREMARC record was retained to assure that it was the one assigned by LC.)

The original intention was to make these OCLC replacement records available for distribution upon their re-load at LC. For various reasons, that distribution was delayed until now. The OCLC replacement subset is being made available for distribution via MDS-Books All and its subsets. It is anticipated that approximately 5,000 to 15,000 records per day will be distributed starting no earlier than April 1, 2005. The encoding level (Leader 17) value is ‘1’.

MDS subscribers are alerted to the following data content within these records:

  1. the descriptive cataloging form (Leader 18) is the value that was in the record at the time it was received by LC from OCLC;
  2. headings and treatment of series are in the state in which they were received by LC from OCLC, e.g., they have not been searched to assure they reflect authoritative forms that may occur in current LC authority files;
  3. choice of main entry is as it was in the record at the time it was received by LC from OCLC; it has not been re-evaluated in the light of AACR2.

Because these replacement records are now several years old and may have been updated in other databases since their receipt in LC, they are being identified with the code “premarc” in field 042.

This will provide subscribers a record-by-record basis for determining whether to load a record or not (to assist this process the OCLC control number is in field 035). If such a replacement record is subsequently fully reviewed at LC and redistributed, the 042 “premarc” code will be removed.

Questions or comments regarding the scope or data content of these records may be directed to:

Mr. Kay Guiles
Cataloging Policy and Support Office
Library of Congress
Washington, DC 20540-4305
email: kgui@loc.gov telephone: (202) 707-4384

March 10, 2005