A scientific adventure story that dramatizes how profoundly our oceans have changed over the past 150 years In December 1872, HMS Challenger embarked on the first round-the-world oceanographic expedition. Its goal: to shine a light for the first time on the mysteries of the deep sea. For the next four years, Challenger's naturalists delved the oceans, encountering never-before-seen marvels of marine life. The expedition's achievements are the stuff of legend: it identified major ocean currents and defining features of the seafloor, including the Mid-Atlantic Ridge and Mariana Trench; it measured worldwide sea temperatures and chemistry, creating baseline data for all ocean research since; and, most spectacularly of all, it collected nearly five thousand sea creatures and plants new to science. In The Wake of HMS Challenger, Gillen D'Arcy Wood looks afresh at this legendary scientific odyssey and shows why, 150 years later, its legacy looms larger than ever. The Challenger's scientists had no way of knowing that the incredible undersea aquarium they were documenting was on the verge of catastrophic change. Off Portugal, they encounter a brilliant starfish now threatened with extinction by microplastics; in St. Thomas, teeming coral habitats that today have been decimated by ocean warming; and at remote Ascension Island, the breeding grounds of the now-endangered green turtle. Lyrical and elegiac, The Wake of HMS Challenger offers a stunning before-and-after picture of our global oceans. It is both a reminder of what we have lost since the Victorian age and an urgent call to preserve what remains of the diverse life and wild beauty of our planet's final frontier.