A natural interface to on-line documentation

Proverbial wisdom suggests that reading manuals is the naturally least favoured method for understanding how to manipulate a mechanism with success. It is therefore surprising that help systems should be regarded as an essential feature of a person-oriented computer system. However, it is accepted that in order to learn how, for example, to express oneself in Z or to determine what is the order of the parameters in a procedure call, documents need to be read. So online help systems should describe the task rather than the means by which the task is done. Since the information may express difficult concepts, the user interface that enables the person to access that information should cause th minimum of cognitive interference. Conventional hypertext based systems, through technically powerful, unfortunately require significant cognitive effort to be expanded on their manipulation and their display metaphors are based on those that pre-date books. An alternative vehicle for accessing information is described in three variations. The vehicle exploits a book metaphor for its display: an evolutionary step which closely follows that through which paper-based methods passed. The result is familiar and comfortable