Virtual reality (VR) is a powerful technology that promises to change our lives unlike any other. By artificially stimulating our senses, our bodies become tricked into accepting another version of reality. VR is like a waking dream that could take place in a magical cartoon-like world, or could transport us to another part of the Earth or universe. It is the next step along a path that includes many familiar media, from paintings to movies to video games. We can even socialize with people inside of new worlds, either of which could be real or artificial. Engineering background of all this magic is worth knowing. Topics Covered: Introduction and About Components Geometry of Virtual World, Light and optics Physiology of Human Vision Visual perception & Rendering Motion in Real and virtual worlds Tracking, Interaction & Audio Evaluating VR systems and experiences Frontiers