This book explores the early-stage detection of cancer using polarized light. It discusses the diverse properties of the light (temporal and spatial coherence, polarization, fluorescence, etc.) that can be used non-invasively as an optical technique for recognizing precancerous lesions, which could become a reliable and accurate method for cancer screening. The search for the effective means for cancer screening is of particular interest to scientific and medical communities, because cancer takes its toll around the globe with no respect for age or gender. Early detection of the disease is a key factor in increasing the survival rate and patients' quality of life.