We think of the Internet as wireless, weightless, ever-present--but its true foundation lies in the ocean's depths, where nearly 900,000 miles of fiber-optic cables quietly pulse with all the world's information.

In The Web Beneath the Waves, the acclaimed journalist Samanth Subramanian travels from remote Pacific islands to secretive cable-laying operations to reveal the astonishing world of undersea infrastructure. He reveals the fate of Tonga after a volcanic eruption severs its only undersea link to the Internet, meets the men and women engaged in the fiendishly complex work of laying submarine cables, and scrutinizes the acts of "grey zone warfare," in which ghost ships cut the cables of other countries.

Subramanian charts the deep geopolitical tensions, corporate power grabs, environmental risks, and quiet heroics involved in maintaining the Internet's unseen circulatory system. With his signature clarity and curiosity, he brings to life the cables that stitch continents together--and exposes just how vulnerable our connected lives really are. This is narrative nonfiction at its most urgent and eye-opening: a book that asks what happens when the world goes offline, and who controls the switch.