Hypertext is a form of electronic book in which the reader, instead of following a preset path from beginning to end, is able to move around by means of selecting key words or phrases within the ‘Book’ that perform a jump to a new location within the ‘Book’.
The term topic in this context refers to a hypertext page of information. Each topic has ar label by which it is accessed, and optionally a title which can be used when performing a search.