The Precipice, boldly dedicated to the 100 billion people before us, the seven billion alive and “the trillions to come, whose existence lies in the balance”, addresses nothing less than the fundamental threats to humanity itself. It is clearly written, approachable and concise for a work tackling such an immense subject, since Ord has confined all subsidiary questions to extensive footnotes and appendices. He begins by setting out “the stakes”, saying that “we live at a time uniquely important to humanity’s future”, dubbing our era the Precipice, as the time of high risk of destroying ourselves.