The fantasy of being transported into another world, to be taken wholly into an imaginary realm, is a primal desire. With computer-based multimedia, encounters with immersive, virtual worlds will soon become commonplace. Virtual reality, after all, is a logical extension of the integration of the arts. It is also an ideal environment for applying our knowledge of human-computer interactivity.

There is an evocative echo in virtual environments of the earliest known form of human expression – the prehistoric cave paintings found at such sites as the caves of Lascaux in the south of France. These immersive environments, dating from 15,000 BC, are thought by scholars to have been theaters for the performance of rituals that integrated all forms of media and engaged all the senses. On the walls were painted animal images and shamanist scrawls, but the environment in which the paintings appeared was surely as significant as the paintings themselves. As Joseph Campbell described it, "these magical spots occur far from the natural entrances of the grottos, deep within the dark, wandering chill corridors and vast chambers, so that before reaching them one has to experience the full force of the mystery of the cave itself." To encounter the cave paintings was to immerse the self in an otherworldly domain, which would heighten consciousness and trigger altered states of perception.

There are many examples of immersion in the history of art. The Dyonisian rituals of Greek Theater, and the construction of the great cathedrals of Europe, are two obvious examples. Richard Wagner's Gesamtkunstwerk was driven by a vision of theater in which the audience loses itself in the veracity of the drama, creating an immersive experience. As he wrote in "The Artwork of the Future," "the spectator transplants himself upon the stage, by means of all his visual and aural faculties." To facilitate his vision, Wagner reinvented the conventions of the opera house, and in 1876 opened the Festpielhaus Theater in Bayreuth, Germany, with the first complete production of The Ring cycle. The Festpielhaus, with its employment of Greek amphitheatrical seating, surround-sound acoustics, the darkening of the house, and the placement of musicians in an orchestra pit, focused the audience's undivided attention on the dramatic action. His intent was to maximize the suspension of disbelief, to draw the viewer into an illusionary world staged within the proscenium arch.

In the 1950s, a similar vision inspired the American cinematographer Morton Heilig to propose a "cinema of the future" that would surround the audience with facsimiles of life so convincing they would believe themselves to be transported to another domain. Such a cinema, he wrote, "would faithfully reproduce man's outer world as perceived in his consciousness, it will eventually learn to create totally new sense materials for each of the senses... [that] they have never known before, and to arrange them into forms of consciousness never before experienced by man in his contact with the outer world."

While Heilig devised a theoretical framework that applied the technologies of his day toward the achievement of virtual experience, it was only as a consequence of advances in computer science that the immersion his work suggested became possible. By 1965, Ivan Sutherland had already achieved legendary status among computer scientists as the inventor of Sketchpad, the first interactive graphics software. In a short paper published that year, Sutherland mused over the options available to the engineer to display computer data, to create a "a looking glass" into what he described as a "mathematical wonderland." It seemed reasonable for him to suggest that "The Ultimate Display" (as the paper was titled) would represent this data in 3-dimensional form, allowing the construction of entirely believable 3-dimensional, computer controlled, virtual worlds. However, like Heilig before him, Sutherland took this suggestion one step further. "The ultimate display," he wrote, "would É be a room within which the computer can control the existence of matter." He suggested that such a display could present realities heretofore only imagined, as if seen through Alice's looking glass. Sutherland's proposal was startling, but it launched an entire field of scientific inquiry.

It also fueled the imagination of a generation of artists. One of the first to consider the possibilities of digitally-constructed virtual experiences was Myron Krueger. In the early 1970s, Krueger created the pioneering works Metaplay and Videoplace to explore the potential of computer-mediated interactivity. These works were interactive artistic environments, influenced by Happenings, designed to give participants freedom of choice and opportunities for personal expression. Videoplace also connected participants in different locations through networked technologies, creating the illusion of shared space. As Krueger later wrote about the piece, "our teleconference created a place that consisted of the information we both shared... a world in which full physical participation would be possible. This world is an 'artificial reality.'"

During the 1970s and 1980s, several engineering projects pursued virtual environment display systems that could represent such an "artificial reality. Perhaps the most significant of these in the mid-1980s was led by Scott Fisher at the NASA-Ames Research Center. Fisher's intent was to engage the entire nervous system in a multi-sensory presentation of virtual space Ð extending multimedia beyond the screen. The Ames VIEW system (an acronym for Virtual Interface Environmental Workstation) included a headset with two small liquid crystal display screens, a microphone for speech recognition, earphones for surround-sound effects, a head-tracking device, and dataglove to recognize the user's gestures and place them within the virtual environment. The direction this work pointed in was clear. As Fisher wrote in his 1989 article "Virtual Interface Environments," "with full body tracking capability, it would also be possible for users to be represented in this [virtual] space by life-size virtual representations of themselves in whatever form they choose." Immersive environments, Fisher observed, could give birth to a new form of participatory, interactive electronic theater.

The possibility of such a theater had already taken hold of the public's imagination. In Neuromancer, his widely read novel from 1984, William Gibson described in palpable detail a future in which virtual reality was a fact of life. Echoing Myron Krueger's notion that teleconferencing created a "place" that consisted of shared information, Gibson's characters inhabited a virtual environment made possible by the networking of computers, which he named "cyberspace." Gibson's cyberspace provided the first literary definition for the computers, hubs, servers, and databases that make up the matrices of the network. His discussion of cyberspace was so tangible Ð and seductive, with its suggestion that any computer hacker could "jack-in to the matrix" with an encounter with a sexy avatar – it became a touchstone for every engineer, artist and theorist working in the field.

Marcus Novak took Gibson's description of virtual environments as the starting point for his own theoretical and artistic explorations. In his essay from 1991, "Liquid Architecture in Cyberspace," he follows the pioneering work of Sutherland, Fisher, and Gibson, et al, to its logical conclusion, and notes its profound implications for architecture, our notions of space, and our attitudes towards the organization of information. He notes that in cyberspace, since all structure is programmable, all environments can be fluid. The artist who designs these immersive digital habitats will be able to transcend the laws of the physical world. As a consequence, architectural forms built in cyberspace can respond to the viewer, encouraging provocative and illuminating interactions. In cyberspace, architecture becomes a form of poetry.

While most research in virtual reality aims to project the viewer into a digital environment by means of a head-mounted display, some engineers have taken an alternative approach. In the early 1990s, Daniel Sandin and Thomas DeFanti conceived of a virtual reality system that places the human body directly inside a computer-generated environment. They describe their system, called the CAVE (an acronym for Cave Automatic Virtual Environment) in their article "Room With a View": "Unlike users of the video-arcade type of virtual reality system, CAVE 'dwellers' do not need to wear helmets, which would limit their view of and mobility in the real world... to experience virtual reality." Instead, participants in the CAVE are surrounded by an immersive, digital "cave painting" -- which brings the evolution of immersion full circle, back to the prehistoric caves of Lascaux, and humankind's earliest efforts at personal expression.