This document provides an overview of face recognition technologies. It discusses applications of face recognition such as security, law enforcement, and entertainment. It describes common face recognition tasks like verification, identification, and search. It outlines challenges in face recognition like variations in pose, expression, lighting, etc. It reviews influential face recognition algorithms from the 1960s to today. It also discusses popular face datasets and benchmark tests. State-of-the-art face recognition systems can achieve over 99% accuracy on constrained datasets but performance decreases significantly for unconstrained images. Research continues to improve face recognition for real-world applications.