The electronic LCSH is the most significant digital tool for the cataloguer, but there are other online versions of LCSH, and ways in which Library of Congress support the work of subject cataloguing generally in a free-to-access manner. The most important of these is the catalogue itself.

The Library of Congress catalogue

Various references have been made to the catalogue of the Library of Congress throughout the text, but it seems sensible to bring them together here. The very existence of the catalogue is a major contributor to the increase in the usage of LCSH, through the easy availability of bibliographic records and their subject cataloguing data. The catalogue is a substantial resource for subject cataloguers in three major ways: the records themselves, the subject index and the authority records.

Accessing the LC catalogue: bibliographic records

A link to the catalogue is to be found on the Library's home page at www.loc.gov. (For UK users it may be worth noting that access to the catalogue is very quick and easy during the morning, but it becomes busier during the afternoon, and you may need several attempts to log in then. Weekends are not usually busy, and although there are occasional periods when the catalogue is down for routine maintenance, these don't usually happen at inconvenient times.)

The home page also provides links to other useful pages, including a number of services and resources specifically for librarians, such as information about MARC, thesauri and vocabulary, metadata standards, and the Cataloging Distribution Service, which markets LC products. Following the link to the catalogue gives you a choice between quick search, basic search, and guided search (Figure 18.1).

Basic search (Figure 18.2) offers a good range of search options and, apart from the most specialized tasks, is the most useful approach for finding records. There are some tips for searching at the bottom of the screen.

Search options include keyword search in all the major aspects of the record (author, title, subject and series). You are limited to a single keyword for each of these, and searching for combinations of keywords requires the use of the Guided Search facility.