From a leading philosopher, an urgent and eye-opening book that makes the case that safeguarding humanity from extinction is the central challenge of our time. From nuclear war and climate change to AI and synthetic biology, the risk of human extinction during this century is frighteningly high. Reducing these risks should be the top global priority-but it isn't. Bringing together key scientific evidence and insight from the humanities, Toby Ord, University of Oxford professor and advisor to the World Bank, U.S. National Security Council, and other global organizations, provides novel tools and concrete strategies for making the largest possible difference in saving our species. The moral argument is simple: society has begun to value diversity across a wide array of genders, races, religions, and sexual orientations, and the Western world is beginning to see the injustice of devaluing those who live in distant countries as well. The next step is to recognize the equality of people distant from us in time-the millions of future generations that should follow our own. The value of many trillions of lives, billions of years of civilization, and untold heights of flourishing and achievement dramatically increases the stakes of existential risks. To destroy such a future would break the partnership across the generations that has raised the human project up to its current heights; it would betray the collective virtues of our civilization; and it might even eliminate the only part of the universe that will ever be capable of appreciating its wonders. Despite the daunting stakes we face, The Precipice resists doom and gloom: Ord's style and message are optimistic, and the book is animated by an inspiring vision of our vast potential.