Introduces two systems that increase the information density of textual presentation by reconsidering text as pictures, expanding the range of written expression. Notes that these systems are implemented as computer programs, active filters that represent textual information graphically. (SR)

Steps aside from conventional ideas about diagrams to examine how they work. Brings to bear ideas from a perceptual psychologist, a communication theorist, and a philosopher. Introduces the papers in this special issue as diagrams for worldmaking. (SR)

Reconsiders the usual typologies of diagram presentations, questioning accepted taxonomies. Examines diagrammatic structures, revealing some hardened categories. Suggests that new discoveries can be made if questions are raised about how information is framed. (SR)