[Vickery in his handbook of procedures for making , writes that organizing a field into facets] can be achieved only by a detailed examination of the… - Brian Campbell Vickery

The most important characteristic of documentary classification is that it is concerned with subjects, not just entities of taxonomic classification. What is the nature of the specific subjects - the themes on which books, parts of books, articles or parts of articles are written? A study of book titles alone would suggest that literary subjects have simple names like 'War, Religion', 'Boats', 'Musica; pitch', 'Colour', 'Acridines', 'Wild flowers', and so on. But the study of articles on the documentation level reveals that such titles are simple in appearance only. Such a literary subject is in reality a complex aggregate of specific subjects, eahc which is the main theme discussed from one particular aspect.

The classification of subject matter may be carried out for all sort of special purposes - to arrange books on shelves, to group inventions in patents, to classify the raw materials, intermediates and products of importance to a particular manufacturer, and so on. All such arrangements have their particular uses and their particular problems.

Information science is concerned with every aspect of the chain of information transfer activities, but the heart of its interest is information search.