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 the unbridled extremes of human behaviour and activity. Traffickers and smugglers, pirates and mercenaries, wreck thieves and repo men, vigilante conservationists and elusive poachers, seabound abortionists, clandestine oil-dumpers, shackled slaves and cast-adrift stowaways: drawing on five years of perilous and intrepid reporting, often hundreds of miles from shore, Urbina introduces us to the inhabitants of this hidden world and their risk-fraught lives.