As Harter (1992) has pointed out, however, a document can be relevant to some information need without being “about” that information need. For example, if I am writing on the subject of barriers to communication, a history of Latin may have some relevance, especially if it deals with the present use of Latin in the Catholic Church and with those organizations that are now trying to promote its wider use. Nevertheless, although I might be able to draw upon this source in my article, few people would claim that it is “about” international communication and it is unlikely to be indexed in this way unless the author explicitly makes reference to the international communication aspect