Ellen Kamhi talks with Dr. Martin Moore-Ede, a world-leading expert on circadian clocks and how light impacts human health. As a professor at Harvard Medical School, he led the team that located the human circadian clock, and showed how it was synchronized by light.  He founded the Circadian Light Research Center which identified the key blue wavelengths that control the circadian clock, and patented & developed the first evidence-based healthy circadian lights. His new book THE LIGHT DOCTOR Using Light to Boost Health, Improve Sleep and Live Longer, makes the compelling case that the light you see is as important to your health as the food you drink, the water you drink, and the air you breathe.