Light-based technologies help diagnose an array of pathological disorders of biological tissues. Innovation and progress in the field of medical science and technologies has enabled medical practitioners to identify various diseases in a non-invasive manner in the initial stages. The optical technologies use laser radiation to capture light-tissue interaction, which helps in obtaining information with respect to the morphological structure and biochemical state of the body area that has been examined. In optical diagnostics, light is passed through the tissues of particular organs of a patient under investigation using optical radiation and the results are recorded. Several imaging and spectroscopic techniques are used in optical non-invasive diagnostics such as laser speckle contrast imaging, optical coherence tomography, optoacoustic tomography, near infrared spectrophotometry, confocal spectroscopy, and fluorescence spectroscopy and imaging. The book aims to shed light on some of the unexplored aspects of optical diagnostics and imaging, and the recent researches in this field. Those with an interest in this field would find this book helpful.