Obsolescence in subject description

Introduction Librarians collect and bibliographers list documents in whatever media and genres (books, journals, data sets, movies, etc.) are expected to be most useful for the communities and the purposes to be served. Once collected, documents need to be made accessible in an organized way. In part this is a matter of scale. A collection of one or very few documents can simply be placed in a list or on a shelf and need neither a catalog nor a systematic arrangement, but making each of a million different documents usefully accessible is a different matter. Effective bibliographical access is usually achieved through very concise descriptions. Svenonius (2000) and Taylor & Joudrey (2009) provide introductions. A current development is the conceptual model for the Functional Requirements for Subject Authority Records (International Federation of Library Associations and Institutions 2010). Librarians assert the subject of a document in two different ways: assigning subject headings to documents’ catalog records and also assigning documents to named subject categories through shelf classification. In Robert Fairthorne’s colorful terms: