On March 3, 1946, a survey began that is, today, the longest-running study of human development in the world, growing to encompass six generations of children, 150,000 people, and some of the best-studied people on the planed. The simple act of observing human life has changed the way we are born, schooled, parent and die, irrevocably altering our understanding of inequality and health. This is the tale of these studies, the scientists who created them, sustained them, and perhaps most importantly, the remarkable discoveries that have come from them. The envy of scientists around the world, The Life Project is one of Britain's best-kept secrets.