Advances in the quality and accessibility of computer graphics has provided new pictorial displays and the tools with which to control them. These new display technologies have focused interest on how to design the static and dynamic images they produce to ensure effective communication. This book, based on the conference on Spatial Displays and Spatial instruments held at the Asilomar Conference Centre in 1987, focuses on the geometry of this communication. It is intended to be a source book of theoretical analysis, experimental demonstrations and practical examples from a range of contributors interested in pictorial communication, from medical artists to astronauts. The book offers the theoretical background and practical guidance needed by designers of contemporary 2D and 3D graphical computer interfaces. Its major contribution lies in its outlining of the elements of human perception and motor control which underlie the geometric design of head-mounted graphics for virtual reality displays.