This book contains the papers presented at the NATO Advanced Study Institute (ASI) on the Basics of Man-Machine Communication for the Design of Educational Systems, held August 16-26, 1993 in Eindhoven, The Netherlands. The ASI addressed the state of the art in the design of educational systems with respect to theories, enabling technologies and advanced applications and implementation issues. The topics discussed are grouped into four main subject areas: 1) Fundamentals of human perception and reasoning, 2) New media: enabling technologies, 3) Artificial Intelligence; software and design techniques, and 4) Advanced applications. This interdisciplinary approach, with a clear focus on the application domain of learning environments, provided the platform for interdisciplinary exchange and communication between the participants. The role of human perception and reasoning was presented in the context of design requirements. The construction of usable human-machine interfaces requires designers to be aware of the inherent competence of the human user. That is, a designer needs to understand the resources that the user brings to the interaction. This includes the general nature of human and world interactions; the nature of the human perceptual system; the natural learning processes by which the information given by the senses is transformed into knowledge of the world; the reasoning processes that allow humans to make inferences from that knowledge once acquired; and the ways in which acquired knowledge may be communicated to others through language.