Bioluminescence is everywhere on earth—most of all in the ocean, from angler fish in the depths to the flashing of dinoflagellates at the surface. Woody Hastings explores the natural history, evolution, and biochemistry of the diverse array of organisms that emit light. Hastings is a leader in the field of photobiology, especially bioluminescence, and is one of the founders of the field of circadian biology (the study of circadian rhythms, or the sleep-wake cycle). He is the Paul C. Mangelsdorf Professor of Natural Sciences and Professor of Molecular and Cellular Biology at Harvard University. He has published over 400 papers and co-edited three books.