In the late 1600s, a distinguished English polymath, Robert Hooke, and an eccentric Dutch cloth merchant, Antonie van Leeuwenhoek, look down their handmade microscopes and discover that complex living organisms are assemblages of tiny, self-contained, self-regulating units. Every part of our bodies is built from these compartments. Hooke christens them cells. The discovery of cells-and the reframing of the human body as a cellular ecosystem-anno...