Copy for rare materials is often poor and sketchy; choosing the best copy requires good judgement on the part of the copy cataloger. Full AACR2 copy is always preferable; however, pre-AACR2 copy is also acceptable. When determining whether an existing bibliographic record corresponds to an item you are cataloging or whether you should create a new record, follow the guidelines in Match Criteria.

1. OCLC

If you find a full AACR2 record in OCLC with a usable call number, your search can stop there. If your copy is pre-AACR2, though, continue your search for better copy. (OCLC AACR2 copy will have an a in the DESC subfield.)

Matching copy in a different format should not be used, since we don't want our holdings to show up on a record in a different format. Treat as an edition copy, and either create a new record or refer.

2. RLIN

The multiple records in each cluster in RLIN can be very helpful when looking for good copy and usable call numbers. If after searching RLIN you still have only pre-AACR2 copy, go ahead and use it. (RLIN AACR2 copy will have an a in the DCF subfield.)

3. NUC pre-1956 (National Union Catalogue) (a.k.a. Mansell)

If you have no matching or edition copy, go on and search the NUC. Packets for mono uncats frequently contain NUC or other copy; compare with item in hand for accuracy.

After deciding on the best copy, review the other copy you found for data elements that may enhance the record created for the CAT. Data elements from other copy may be used in the record created for the CAT only if they accurately reflect description of the item in hand. These data elements or fields may then be manually keyed into the record created. Call numbers can be taken from near copy if a usable call number is not on the copy you have chosen.

If additional subjects are found on other copy, or if there is uncertainty regarding the call number, these fields may be identified on a printout and referred for subject cataloging. Do not add or manipulate Subject Headings without appropriate training; refer as needed.

If no usable copy is found in the CAT or on the utilities, refer for Original Cataloging.