There are 100,000 freighters on the seas. Between them they carry nearly everything we eat, wear and work with. And yet this massive global industry has remained largely unexamined: it passes by out of sight for most of us and, through the 'flags of convenience' system, its dubious practices often slip under the radar of regulators.

In this unique investigation, Rose George travels the high seas with their powerful naval fleets, pirate gangs, and illegal floating factories, and visits the ports and their land-bound dockworkers, tycoons, missionaries, stevedores, border control guards, and ship-spotters. She meets the beachcombers who track the 10,000 containers that are lost every year, the robots who are gradually replacing human crews, and the environmentalists campaigning against the tide of marine pollution. Intrepid, informed and tenacious, George steers a sure course through the murky, character-rich waters of international shipping.