This document provides an introduction to augmented reality (AR) and its components and applications. It discusses how AR supplements reality by overlaying virtual objects on the real world. The key components of an AR system include head-mounted displays, tracking systems, and mobile computing power. Applications mentioned include medical, manufacturing, aircraft maintenance, and providing instant information. Challenges with AR include accurate registration of virtual and real objects and reducing motion sickness. The conclusion is that while AR is still developing, it has potential for improving navigation and interaction between real and virtual worlds.