This document discusses augmented reality (AR), which enhances the real world with computer-generated perceptual information. AR is defined as enhancing the real world rather than completely replacing it like virtual reality. The document then discusses how AR works by superimposing graphics, audio and other senses onto real-world scenes. Examples of AR technologies like Hawk-Eye and Sixth Sense are provided. Applications of AR discussed include travel, transportation, medicine, and advertising. Limitations and the future of AR are also mentioned.