Taking a broad yet detailed approach, this comprehensive handbook covers light-based diagnostic methodologies and light-mediated therapeutics as well as concepts and cutting-edge optical methods used in research and practice. Extensively illustrated, the book presents the theory and fundamentals, along with state-of-the-art applications. The expert contributors also discuss advantages and disadvantages of various techniques. After introducing the background principles of optics, light sources, and irradiation and basic tissue optics concepts, the book focuses on spectroscopic methods, tomographic imaging, microscopic imaging methods, molecular probe development, and phototherapy.