In this "essential guide to the half of our blue planet we call the high seas" (Will McCallum, author of How to Give Up Plastic), one of the world's leading voices on the issue tracks the race to exploit and protect our last frontier.

Two thirds of the world's oceans lie beyond national borders. Owned by all nations and no nation simultaneously, the high seas are home to some of the richest and most biodiverse environments on the planet. But they are also home to exploitation on a scale that few of us have imagined.

Here, out of sight and out of mind, industry and economic progress rule and lax enforcement and apathy are the status quo, underscored by a battle to control, profit from, protect, or obliterate the world's largest, wildest commons. In this book, Heffernan uncovers the truth behind deeply exploitative fishing practices, investigates the potentially devastating impact of deep-sea mining, and holds to task the Silicon Valley interventionists whose solutions to climate change are often wildly optimistic, radically irresponsible, or both. This is a powerful and deeply researched manifesto calling for the protection and preservation of this final frontier.