For many researchers virtual reality (VR) is first of all a technology. This vision is also well reflected in the growing research work concerned with virtual environments: most of it has addressed more the development of new rendering technologies rather than the highly interactive and dynamic nature of user-system interaction that VR supports. However, this focus on technology is disappointing for developers and researchers. To overcome this limitation, the book describes VR as an advanced communication tool: a communication interface in single-user VR, and a communication medium in the case of multi-user VR. This book is part of a general inquiry into the implications of new technologies like VR. The shifting structures of communication systems present historic opportunities and challenges for communication researchers and that these require multidisciplinary approaches to communication research. Virtual reality may become the ship that helps us sail the vast oceans of cyberspace. This book is our attempt to construct a paper telescope to scan the horizon for signs of communication (and life) in the age of virtual reality.