Hamnet is the online catalog of the Folger Shakespeare Library's collection. It contains hundreds of thousands of records for books, manuscripts, prints, DVDs, objects, e-resources, and other material, but does not describe everything in the collection. Many manuscripts, for example, are instead described in online finding aids, and other materials are still only described in the card catalogs and other paper-based resources.
Hamnet debuted in 1997. The name was chosen through a competition open to staff and readers, and evokes both Shakespeare ("Hamnet" was the name of his son, "Hamlet" is one of his best-known plays) and the Internet (often called just "the Net" in the 1990s).
Hamnet records are encoded in MARC (which stands for "MAchine-Readable Cataloging"), a data format developed at the Library of Congress in the late 1960s that quickly became the international standard for libraries. All MARC fields searchable from the "Advanced" tab in Hamnet are listed in Folgerpedia's List of keyword search fields in Hamnet and their associated MARC codes.