This document summarizes a research paper on face recognition techniques. It discusses the history of face recognition research from the 1950s to present. Early work focused on identifying faces using geometric measurements of facial features. In the 1980s, neural networks and eigenfaces approaches using principal component analysis were introduced. The document also outlines common problems in face recognition systems, including variations in scale, illumination, expression, and noise. Finally, it reviews literature on human and machine face recognition systems.