The use of light in medical diagnostics, therapeutics, and biomedical research is increasing, driven by advances in light sources, imaging detectors, fiber-optic delivery and sensor systems, better understanding of light-tissue interactions, and increasing number of translated research and clinical applications. The course will focus mostly on in vivo photonics and initially cover 1) the relevant issues of light propagation in / interaction with turbid media such as tissue. The bulk of the course will focus on 2) particular technical implementations and research / pre-clinical / clinical results in photo-diagnostics (effects of tissue on light) and photo-therapeutics (effects of light on tissue). Advanced topics such as 3) molecular imaging, nanophotonics, optical clearing and theranostics will also be briefly covered. As such, the course goals relate to obtaining basic competencies in these 3 areas. For students with limited background in optics and photonics, we will also run a series of tutorials to provide some "light" basics we deem useful for the course. These will be offered prior to the module itself, and will be optional for interested students. The tutorial will not count toward course evaluation.