Hypertext Construction: In constructing an application, a developer must parse information into small, discrete units (nodes) which consist of a single concept or idea. Nodes should be both semantically and syntactically discrete, representing a single idea or thematic statement. These idea units, or nodes, which are usually displayable on one screen, can be classified as either "untyped" or "typed". Untyped nodes are idea units that have no label or descriptor to identify the information they contain. Typed nodes are labeled as a means of classifying the nodal information and defining particular nodal applications. The Assembly of a Hypertext System Associative links establish nodal relationships and connect individual ideas to related points, sources, ancillary information, and annotations. As with the nodes, the links themselves can be assigned "type". The origin of an associative link is a point called "link reference". This "point" is a character, token, or icon that identifies a link in a document. A link destination consists of a node or region of text (or graphics, etc.), and is called a "link referent" (Fiderio, 1988). Links provide the primary means of discretionary navigation through the network and hierarchical structure of a hypertext system. CRISTAL Data Links Four Types of Hypertext Hypertext Navigation Hypertext Faults Knowledge Communities