Circadian timekeeping is fundamental to human health. Unfortunately, under many clinical circumstances, the temporal organization of our minds and bodies can stray slowly from the Universal Time UT) that is set with the Earth’s rotation. This disorganization has been linked to progression of several age-related and psychiatric diseases. Non-invasive phototherapy has the potential to improve disease outcomes, but the information that the brain’s clock tracks in twilight or any electric light signal) to assure that a person entrains their sleep-wake cycles to the outside world is not understood. The central theme of my research program is to fill in this blank and to usher in an era where therapeutically relevant “high-precision” light administration protocols are institutionalized at the level of the American Medical and Psychiatric Associations to change the standard of care for a wide variety of conditions that impair quality of life. Of the conditions my lab is currently studying, we are particularly interested in how chronic and quick, sequenced light exposure can be designed to: 1. promote normal healthy aging and 2. strengthen adaptive cognitiveotional responses to being awake in the middle of the night 12-6AM) a key interval of the 24-h cycle that we have associated with increased suicidal ideation and mortality. Our circadian work on suicide is done in very close partnershiwith the University of Arizona SleeHealth and Research Program directed by Dr. Michael Grandner.