This Handbook, with contributions from leading experts in the field, provides a comprehensive, state-of-the-art account of virtual environments (VE). It serves as an invaluable source of reference for practitioners, researchers, and students in this rapidly evolving discipline. It also provides practitioners with a reference source to guide their development efforts and addresses technology concerns, as well as the social and business implications with which those associated with the technology are likely to grapple. While each chapter has a strong theoretical foundation, practical implications are derived and illustrated via the many tables and figures presented throughout the book. The Handbook presents a systematic and extensive coverage of the primary areas of research and development within VE technology. It brings together a comprehensive set of contributed articles that address the principles required to define system requirements and design, build, evaluate, implement, and manage the effective use of VE applications. The contributors provide critical insights and principles associated with their given area of expertise to provide extensive scope and detail on VE technology. After providing an introduction to VE technology, the Handbook organizes the body of knowledge into five main parts: *System Requirements--specifies multimodal system requirements, including physiological characteristics that affect VE system design. *Design Approaches and Implementation Strategies--addresses cognitive design strategies; identifies perceptual illusions that can be leveraged in VE design; discusses navigational issues, such as becoming lost within a virtual world; and provides insights into structured approaches to content design. *Health and Safety Issues--covers direct physiological effects, signs, symptoms, neurophysiology and physiological correlates of motion sickness, perceptual and perceptual-motor adaptation, and social concerns. *Evaluation--addresses VE usability engineering and ergonomics, human performance measurement in VEs, usage protocols; and provides means of measuring and managing visual, proprioceptive, and vestibular aftereffects, as well as measuring and engendering sense of presence. *Selected Applications of Virtual Environments--provides a compendium of VE applications. The Handbook closes with a brief review of the history of VE technology. The final chapter provides information on the VE profession, providing those interested with a number of sources to further their quest for the keys to developing the ultimate virtual world.