The emergence of high-speed networking for multimedia will have the effect of turning the computer screen into a window on a very large information space. As this information space increases in size and complexity, providing users with easy and intuitive means of accessing information will become increasingly important. Providing access to large amounts of text has been the focus of work for hundreds of years and has resulted in the evolution of a set of standards, from the Dewey Decimal System for libraries to the recently proposed ANSI standards for representing information on-line: KIF, Knowledge Interchange Format, and CG's, Conceptual Graphs. Certain problems remain unsolved by these efforts, though: how to let users know the contents of the information space, so that they know whether or not they want to search it in the first place, how to facilitate browsing, and, more specifically, how to facilitate visual browsing. These issues are particularly important for users in educational contexts and have been the focus of much of our recent work. In this paper we discuss some of the solutions we have prototypes: specifically, visual means, visual browsers, and visual definitional sequences.