In the last chapter on alphabetical subject access we looked at some of the general considerations of alphabetical subject work and the problems (and their solutions) that arise when we use words as the basis of retrieval. While it's perfectly possible to develop an in-house subject indexing system based on the concept analyses for individual documents, the intellectual effort involved and the high cost of maintenance required mean that most libraries opt to use a published standard. In the vast majority of cases that standard will be the Library of Congress Subject Headings (LCSH). During the last twenty years of the 20th century many academic libraries in the UK began to use LCSH, even if they were not using the Library of Congress Classification, and it is used, in English in 24 national libraries, and in 12 others in translation. This is in addition to its long-established use in the United States and Canada. The only other set of English language general subject headings in common use is Sears’ List of subject headings for a small library, which, as the name suggests, is much less extensive than LCSH. While many countries have their own national standards for subject headings (such as Nuovo Soggettario in Italy), others use adaptations or modifcations of LCSH, such as the Canadian Répertoire de vedettes-matière.

What is LCSH?

LCSH is an alphabetical list of the headings that are used in the subject catalogues of the Library of Congress, together with ‘thesaural’ crossreferences that enable classifiers to find other appropriate headings. A typical section of LCSH looks something like this:

When we come to the section on practical application of LCSH we'll look in detail at the layout, and at what the different cross-references and typographical variations mean, so you don't need to worry about these at this stage.