Labels and records
Introduction to MARC 21 for Cataloging Staff
MARC 21 provides formats for representing and exchanging library data. Learning to recognize a few fields helps you inspect records, but a short field list is not enough to create a complete valid record. Begin by separating the data format from the rules used to describe a resource.
Recognize the parts of a field
A MARC display uses a three-character tag to identify a field. Many variable data fields have two indicator positions and labeled subfields. Their meanings depend on the field: the same subfield letter is not a universal column name. The Library of Congress MARC standards are the reference point for the formats.
When examining an unfamiliar field, look it up rather than guessing from a similar tag. Check whether the field and its subfields can repeat, how blank indicators are represented in your editor, and which values are controlled. A display convention such as # for a blank is not necessarily a character to type into the underlying data.
Read a small title example
100 1# $a Rivera, Maya, $e author.
245 14 $a The neighborhood archive : $b a staff workbook / $c Maya Rivera.These invented fields are a teaching fragment, not an importable record or an established name authority. In this 245 example, the first indicator requests a title added entry and the second counts four nonfiling characters: “The” plus the following space. Subfield $a holds the title proper, $b the remainder of the title, and $c the statement of responsibility. See the LC introduction to MARC fields.
Notice that the display still retains “The.” Filing treatment is not an instruction to delete the article from the transcribed title. Similarly, a generator’s title-workmark shortcut should never be used as a rule for editing a MARC title field.
Keep bibliographic and item data distinct
A shared description can support several locally held copies. A barcode, local location, or copy status belongs in the library’s appropriate holdings or item workflow, which may be stored separately from the bibliographic record. Ask how your system maps these values before exporting or moving data.
For a small exercise, select a known two-copy title and compare its bibliographic view with its item view. Identify what is shared and what changes between copies. This makes it much easier to avoid changing a common description when only one item has moved.
Use CSV for its limited purpose
LibCatalogTools’ CSV is a label input format. It does not preserve a MARC leader, directory, control fields, indicators, repeated fields, or the complete descriptive record. Downloading an updated label CSV therefore does not produce a MARC export.
- Keep the original MARC export or source record intact.
- Extract only the reviewed values needed for labels.
- Check the label output against the catalog.
- Use your cataloging system’s validated import process for any record changes.
Frequently asked questions
Is MARC 21 the same as a cataloging content standard?
No. The format represents data; your adopted descriptive rules determine much of the content entered into it.
Can I import the example as a complete record?
No. It is an explanatory fragment and lacks the rest of a complete record.
References and further reading
Official references support the standards discussed here. Worked examples and local workflow suggestions are instructional illustrations.