Harper Academic

The Deepest Map

The High-Stakes Race to Chart the World's Oceans

by Laura Trethewey

On Sale: 07/08/2025

Price: $18.99

The Deepest Map

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The Deepest Map

The High-Stakes Race to Chart the World's Oceans

by Laura Trethewey

On Sale: 07/08/2025

Format:

Price: $18.99

About the Book

A SCIENCE NEWS MAGAZINE BEST BOOK OF 2023

A GLOBE AND MAIL BEST NONFICTION BOOK OF 2023

“Should be required reading. . . . A gripping and all-too-timely account of what in more ways than one is turning out to be a very costly and questionably necessary race to the bottom. . . . Trethewey rises to the occasion here, relating in absorbing detail the ebb and flow of conflicting interests that tussle down among the vents and ridges of the hadal zone. It is all highly readable, and it is all deeply ominous.” —Simon Winchester, New York Times Book Review

The dramatic and action-packed story of the last mysterious place on earth—the world’s seafloor—and the deep-sea divers, ocean mappers, marine biologists, entrepreneurs, and adventurers involved in the historic push to chart it, as well as the opportunities, challenges, and perils this exploration holds now and for the future.

Five oceans—the Atlantic, the Pacific, the Indian, the Arctic, and the Southern—cover approximately 70 percent of the earth. Yet we know little about what lies beneath them. By the early 2020s, less than twenty-five percent of the ocean’s floor has been charted, most close to shorelines, and over three quarters of the ocean lies in in what is called the Deep Sea, depths below a thousand meters. Now, the race is on to completely map the ocean’s floor by 2030—an epic project involving scientists, investors, militaries, and private explorers who are cooperating and competing to get an accurate reading of this vast terrain and understand its contours and environment.

 In The Deepest Map, Laura Trethewey documents this race to the bottom, following global efforts around the world, from crowdsourcing to advances in technology, recent scientific discoveries to tales of dangerous dives in untested and costly submersibles. The lure of ocean exploration has attracted many, including the likes of James Cameron, Richard Branson, Ray Dalio, and Eric Schmidt. The Deepest Map follows a cast of intriguing characters, from early mappers such as Marie Tharp, a woman working in the male-dominated fields of oceanography and geology whose discoveries have added significantly to our knowledge; Victor Vescovo, a man obsessed with reaching the deepest depths of each of the five oceans, and his young, brilliant, and fearless mapper Cassie Bongiovanni; and the diverse entrepreneurs looking to explore and exploit this uncharted territory and its resources.

In The Deepest Map, ocean discovery converges with humanity's origin story; in mapping the ocean floor, scientists are actively tracing our roots back to the most inhospitable places on earth where life began—and flourished. But for every conservationist looking to protect the seafloor, there are others who see its commercial potential. Will a new map exacerbate pollution and the degradation of this natural resource? How will the race remake political power structures in years to come? Trethewey probes these questions as countries and conglomerates wrestle over the riches that may lie at the bottom of the sea.

The future of humanity depends on our ability to protect this vast, precious, and often ignored resource. A true tale of science, nature, technology, and an extreme outdoor adventure The Deepest Map illuminates why we love—and fear—the earth’s final frontier and is a crucial addition to the increasingly urgent conversation about climate change.

Critical Praise

"An engrossing look at deep-sea exploration. Essential reading for environmentalists, armchair adventure divers, and those who care about the world’s oceans." — Kirkus (Starred Review)

"There is no doubt in my mind that the ocean plays the most massive role in our past, present, and future—from transportation to planet health to long term sustainability. The Deepest Map shines a light on this massive yet ever-changing force and helps bring into focus so many unanswered questions, while giving us a beautiful reminder of how important it is to educate and protect these waters to the best of our abilities."
Garrett McNamara, Big Wave surfer, co-creator of the documentary series 100 Foot Wave and author of Hound of the Sea

“[The] questions Trethewey encourages us to ponder in The Deepest Map are not centered around whether to map and explore the deep sea, they’re about how that exploration happens, who controls it, and what it leaves behind. The deep sea could become our next Amazon…heavily plundered and degraded. Or it could become our next Antarctica, governed by international treaties that protect it in the name of science. Trethewey’s thorough accounting of our knowledge of and relationship to this ‘last truly mysterious place on Earth’ can only help us along the right path.” — Atlantic Books Review

"Wow, what a great adventure story. Shipwrecks, octopus gardens, coral reefs as tall as the Empire State Building, 11,000 year-old sponges, deep sea robots—it’s a trip to another world, right here on Earth. This is not just a book about the epic quest to map the ocean floor, but an exploration of the mysteries and life of a planet we hardly know. The Deepest Map is one of those rare books that will change the way you see our world." — Jeff Goodell, author of The Water Will Come

"Trethewey’s sharp eye for character brings out the humanity in the marine moonshot. It’s worth exploring." — Publishers Weekly

"A riveting ocean of a book, packed with gripping adventures, high-stakes exploration and political intrigue. Trethewey leads us to the bottom of the sea and deftly shows why it all matters so much." — Helen Scales, author of The Brilliant Abyss

"The Deepest Map is a fascinating, poetic love letter to our planet and to the scientists and explorers risking their lives to understand its unconscious. With exhaustive reporting, Trethewey takes us on an awe-inspiring and humbling adventure that makes us realize how much we still have to learn about our home." — Jaimal Yogis, author of All Our Waves Are Water

"This adventure on the high seas follows scientific explorers who are charting the seafloor in exquisite detail. But as with any exploration of uncharted territory, mapping the bottom of the ocean risks spoiling a place largely untouched by humans." — Science News Magazine

"A gripping, timely account of the world’s push—by inventors, scientists, business people and government—to map the ocean’s floor." — The Globe and Mail

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Product Details

  • ISBN: 9780063099968
  • ISBN 10: 0063099969
  • Imprint: Harper Paperbacks
  • On Sale: 07/08/2025
  • Trimsize: 5.310 in (w) x 8.000 in (h) x 0.000 in (d)
  • Pages: 304
  • List Price: $18.99
  • BISAC1 : NATURE / Ecosystems & Habitats / Oceans & Seas
  • BISAC2 : SCIENCE / Earth Sciences / Oceanography
  • BISAC3 : BUSINESS & ECONOMICS / Environmental Economics