Five oceans cover approximately seventy per cent of the earth, yet we know little of what lies beneath them. Now, the race is on to completely map the oceans’ floor. Scientists, investors, militaries, and private explorers are competing in this epic venture to obtain an accurate reading of this vast terrain and understand its contours and environment. In The Deepest Map, Laura Trethewey chronicles this race to the bottom. Following global efforts around the world, she documents Inuit-led crowdsourced mapping in the Arctic as climate change alters the landscape, a Texas millionaire’s efforts to become the first man to dive to the deepest point in each ocean, and the increasingly fraught question of whether and how to mine the deep sea. A true tale of science, nature, technology, and extreme outdoor adventure, The Deepest Map both illuminates why we love — and fear — the earth’s final frontier and contributes to increasingly urgent conversations about climate change.