Hypertext Navigation:

The ability of the user to browse through information nodes is a
fundamental attribute of hypertext.  However, in large hypertext
systems a user can quickly lose a sense of context and
orientation if additional navigational aids are not present.  A
"graphical browser" is a structural diagram of nodal networks,
and can graphically communicate the user's position in the
information base.  The information "path" is either a user
defined or a default route through an information network.  A
"filter" suppresses detail and allows quick scanning of network
information and associative relationships to facilitate user
orientation within the knowledge base (Fiderio, 1988).

<cfile27>   Memex
<cfile31>   Hypertext Construction
<cfile36>   Road Maps: Navigating a Knowledge Base