There are few remaining frontiers on our planet. But perhaps the wildest, and least understood, are the world’s oceans: too big to police, and under no clear international authority, these immense regions of treacherous water play host to rampant criminality and exploitation.

Traffickers and smugglers, pirates and mercenaries, wreck thieves and repo men, vigilante conservationists and elusive poachers, seabound abortion providers, clandestine oil-dumpers, shackled slaves and cast-adrift stowaways — drawing on five years of perilous and intrepid reporting, often hundreds of miles from shore, Ian Urbina introduces us to the inhabitants of this hidden world. Through their stories of astonishing courage and brutality, survival and tragedy, he uncovers a globe-spanning network of crime and exploitation that emanates from the fishing, oil and shipping industries, and on which the world’s economies rely.