This document discusses augmented reality (AR), its components, how it works, applications, and limitations. It defines AR as enhancing the real world with digital information. The key components of AR are head-mounted displays, tracking systems, and mobile computing power. AR works by tracking positions, computing, and displaying virtual objects in the real world. Applications discussed include using AR for color blindness assistance, medical procedures, education, and Google Glass. Limitations include accuracy of tracking, lack of computing power for 3D graphics, and size of AR systems.