This book exposes the root of our current predicament: how big tech's relentless focus on optimization is driving a future that reinforces discrimination, erodes privacy, displaces workers, and pollutes the information we get. Armed with an understanding of how technologists think and exercise their power, three Stanford professors--a philosopher working at the intersection of tech and ethics, a political scientist who served under Obama, and the director of the undergraduate Computer Science program at Stanford (also an early Google engineer)--reveal how we can hold that power to account.