A golden era of deep-sea discovery is underway as revolutionary studies rewrite the very notion of life on Earth and the rules of what is possible. In the process, the abyss is being revealed as perhaps the most amazing part of our planet, its topography even more varied and extreme than its landmass counterpart. Teeming with unsuspected life, an extraordinary, interconnected ecosystem deep below the waves has a huge effect on our daily lives, influencing climate and weather systems, with the potential for much more-good or bad, depending on how it is exploited. Currently, the fantastic creatures that live in the deep-many of them incandescent in a world without light-and its formations capture and trap vast quantities of carbon that would otherwise poison our atmosphere, and novel bacteria as yet undiscovered hold the promise of potent new medicines. Yet the deep also holds huge mineral riches lusted after by nations and corporations; mining them could ultimately devastate the planet, compounded by the deepening impacts of ubiquitous pollutants and rampant overfishing. Eloquently and passionately, the author of Spirals in Time and Eye of the Shoal brings to life the majesty and mystery of an alien realm that nonetheless sustains us, while urgently making clear the price we could pay if it is further disrupted.