Virtual reality
The 1990s saw the first widespread commercial releases of consumer headsets. In 1991, Sega announced the Sega VR headset for arcade games and the Mega Drive console. It used LCD screens in the visor, stereo headphones, and inertial sensors that allowed the system to track and react to the movements of the user's head. In the same year, Virtuality launched and went on to become the first mass-produced, networked, multiplayer VR entertainment system. It was released in many countries, including a dedicated VR arcade at Embarcadero Center in San Francisco. Costing up to $73,000 per multi-pod Virtuality system, they featured headsets and exoskeleton gloves that gave one of the first "immersive" VR experiences. "Computer Gaming World" predicted "Affordable VR by 1994".
Artificial Reality
Artificial reality is a book series by Myron W. Krueger about interactive immersive environments (or virtual realities), based on video recognition techniques, that put a user in full, unencumbered contact with the digital world. He started this work in the late 1960s and is considered to be a key figure in the early innovation of virtual reality. "Artificial Reality" was published in 1983 and updated in "Artificial Reality II" in 1991 (both published by Addison-Wesley).