Deep is a voyage from the ocean's surface to its darkest trenches, the most mysterious places on Earth. Fascinated by the sport of freediving - in which competitors descend to great depths on a single breath - James Nestor embeds with a gang of oceangoing extreme athletes and renegade researchers. He finds whales that communicate with other whales hundreds of miles away, sharks that swim in unerringly straight lines through pitch-black waters, and other strange phenomena.
In 1948, a young Australian mining engineer named Ben Carlin set out to do the impossible: circumnavigate the globe, by land and sea, in a single vehicle. The vehicle in question was an amphibious jeep developed by the U.S. Army, which Carlin christened Half-Safe, after a deodorant slogan. It was a mechanical mongrel that was supposed to move with equal ease across land and water but in practice wasn't much good for either one. Undaunted, Carlin and his wife Elinore set off across the Atlantic Ocean with dreams of fame and fortune, and of carving a small notch in history.