An awe-inspiring investigation into the hidden world of the deep sea--the most mysterious, unforgiving environment on Earth--whose secrets can radically revise our understanding of life itself and chart our planetary future. "A brilliant scientist and storyteller, Jeffrey Marlow takes us on a page-turning descent into the deepest mysteries on the planet."--Jack E. Davis, Pulitzer Prize-winning author of The Gulf: The Making of an American Sea The deep sea is our planet's last frontier. For most of human history, it was a vast, unknown realm that invoked awe and terror. And despite how much we've learned, it remains largely unexplored. In The Dark Frontier, marine microbiologist and explorer Jeffrey Marlow offers a new perspective on the power and beauty of the deep sea, beginning with the nineteenth-century discovery that the ocean's depths were teeming with life and shifting to more recent investigations of the kaleidoscopic ecology of hydrothermal vents, methane seeps, and whale falls. Marlow illuminates the ocean's scientific marvels, including microbes that breathe metal and fish that withstand crushing pressures, as well as theories about how underwater habitats may have been the cradle of life on Earth. He reveals the deep sea's microbial universes, worlds within worlds that have opened new possibilities of survival in extreme environments. The Dark Frontier is an engaging narrative journey grounded in Marlow's research and wide-ranging knowledge, together with insights from hundreds of experts, from deep-sea scientists to conservationists and UN diplomats. The book considers the twinned forces of exploration and exploitation, shining a light on deep-sea drilling and mining as well as the complexity of governing the high seas and their precious resources. In this authoritative and accessible account of ocean exploration, Marlow captures the wonder and potential of the deep sea, teaching us lessons that help navigate the future--not just for the remarkable creatures that live there but for those of us on the surface as well.