Pictorial Communication: in virtual and real environments analyzes com- munication which develops between human users and machines in envi- ronments provided by general and special purpose computers.

The analysis is based on a metaphor illustrated by the unusual environment described by Astronaut Joseph Allen during capture of the Palapa and Wes- tar satellites. While controlling his Manned Maneuvering Unit, a manually driven spacecraft without extensive automatic control, he interacted with unusual objects, was freed from the ordinary kinematic constraints experi- enced on earth, and directly experienced the counter-intuitive dynamical properties of orbital mechanics.

These three facets of his experience illustrate three principle aspects of an environment: its content, the objects and actors it contains; its geometry, the allowable changes in the absence of exchange of energy or information; and its dynamics, the changes in objects due to the exchange of energy and in- formation. These three dimensions of an environment's definition offer al- ternative ways to enhance communication among the actors and objects in it.

The 39 chapters of the book address the scientific and engineering issues that arise when pictorial communication must be designed for the synthetic environments. Specific environmental examples are provided by virtual- image-head-mounted computer displays, panel-mounted pictorial displays or by real but unusual environments such as outer space.