A pioneering marine biologist takes us down into the deep ocean to dunderstand bioluminescence--the language of light that helps life communicate in the darkness--and what it ells us about the future of life on Earth. Edith Widder's childhood dream of becoming a marine biologist was almost derailed in college when complications from a surgery gone wrong made her temporarily blind. Her new reality of shifting shadows drew her fascination to the power of light--as well as to the importance of optimism. As her vision cleared, Widder found the intersection of her two passions in oceanic bioluminescence, a little-explored scientific field within Earth's last great unknown frontier: the deep ocean. With little promise of funding or employement, she leaped at the first opportunity to train as a submersible pilot and dove into the darkness. Widder's first journey into the deep ocean, in diving gear that resembled a suit of armor, took her down to eight hundred feet. Turning off her lights, she