Kyle Harper explains why humanity's uniquely dangerous disease pool is rooted deep in our evolutionary past, and why its growth is accelerated by technological progress. He shows that the story of disease is entangled with the history of slavery, colonialism, and capitalism, and reveals the enduring effects of historical plagues in patterns of wealth, health, power, and inequality. He also tells the story of humanity's escape from infectious disease--a triumph that makes life as we know it possible, yet destabilizes the environment and fosters new diseases.