Light from the sun produced life on earth. Light plays major important functions that are important for our wellbeing including image-vision, adjusting our internal biological rhythms to match the solar day which influence our sleep and enhancing mood. We have made incredible advances in understanding how light achieves these functions. In this discussion, Samer Hattar, of the National Institute of Mental Health, will provide exciting tidbits on how to use light to enhance your sleep and mood.