PROGRESS IN DOCUMENTATION: ‘obsolescence’ and changes in the use of literature with time Available to Purchase

The term ‘obsolescence’ occurs frequently in the literature of librarianship and information science. In numerous papers we are told how most published literature becomes obsolete within a measurable time, and that an item receives half the uses it will ever receive (‘half‐life’) in a few years. ‘Obsolescence’ is however very rarely defined, and its validity, interest, and practical value are often assumed rather than explained. Before reviewing studies on ‘obsolescence’, therefore, it is necessary to look at the concept and to identify the reasons why it should be of interest.