This page is meant to be a short guide to working with MARC bibliographic records for those who do not normally create or edit them, but would like to better understand how the library catalog works, or want to use MARC records in their research. If you are looking for the Folger’s MARC documentation, please see the main MARC page.
Introduction to MARC
The MARC format was developed by Henriette Avram at the Library of Congress in the late 1960s to enable the transfer and manipulation of catalog data by computers. Instead of having to re-type the same information again and again on 3" x 5" index cards, catalogers could re-purpose information already entered, add what they needed for their own use, and print as many cards as they needed (to file under author, title, subjects, etc.). Records in the Folger catalog and many other electronic library catalogs are still very brief, having originally been intended for print-out on index cards, or copied from pre-MARC hand-typed index cards.
At first, only librarians had access to the electronic information, but in the 1980s computer terminals for public access to a library’s holdings began to be available. Because these terminals showed networked data, not data stored on just that machine or a CD-ROM for instance, they became known as Online Public Access Catalogs, or OPACs (pronounced OH-packs). The term is still used by librarians, even though the notion of an "offline" electronic catalog is long gone.
MARC was designed to handle authority records (officially-established forms of names and subjects), bibliographic records (generic descriptions of books and other items in a library’s collections), and holdings records (copy-specific information about the same material, including local call numbers). MARC is primarily meant to be machine-readable, but most fields can be formatted as eye-readable; however, it can seem overwhelming at first. To get a sense of what eye-readable MARC looks like, if you haven’t worked with it before, open a Folger catalog record, select the Formats button, then select the "View" button next to "MARC". You should see something like this:
MARC view of The reign of the horse (Folger Library Publications, 1991)