The ancestor of what we refer to as virtual reality was the Sensorama, developed by Morton Heilig in the 1950's. But, one of the first really useful applications of virtual reality technology was in the military, where it was primarily used for training and for simulation. It was not long, however, before virtual reality found its way into mainstream America and could be utilized by anyone. At first, virtual reality was very primitive, but over time it has grown extensively. Now it can be used for many different purposes ranging from advanced car and plane simulators to the simplest video games.Today the most sophisticated virtual reality systems are in development all around the world. The market for virtual reality technology systems has grown well beyond the military in the past ten years. Airlines are using virtual reality for pilot training and the consumer demand for virtual reality is increasing exponentially. The consumer applications of the technology are apparent in products such as Apple's QuickTime VR and QuickTime 3D. Public virtual reality "cafés" such as New York's XS are becoming increasingly common.

The most visible parts of the virtual reality experience are the objects used directly by the user such as stereo-optical visors, position-sensing gloves, wands, sensors, and biosensors.This equipment provides the computer with the information necessary to successfully immerse the user. The center of the virtual reality system is the "reality engine," which makes up the computer system as well as the stereo and video processors. These things provide the system with the sensory data which help make the environment seem more realistic.

One of the coolest things about virtual reality is that it is subject to natural forces, like light and gravity. Virtual reality that is well done can look like a motion picture on your computer screen. A person using virtual reality can feel like they are really a part of the situation, even though its not really real. One of the most common applications of virtual reality is the use of simulators. Video games are also becoming increasingly more virtual reality oriented.

There are also practical applications of virtual reality. An example would be "virtual memory," which uses RAM to simulate the behavior of a Hard Disk. It may be slower, but it does work! Other things that virtual reality is used for are virtual private network, which is a kind of communications network, virtual sex and pornography, which is becoming increasingly popular on the Internet, and virtual theme parks, which offer opportunities to have some fun without having to go anywhere.

Virtual reality is made possible through the use of realtime 3-D modelling, position-tracking, and stereo-audio techniques. The aspect of virtual reality that makes it different from other computer games and such is that virtual reality breaks the user/screen interface, which puts the user in an environment which seems almost real, and certainly more real than what they were using before.