The Life Project: The Extraordinary Story of 70,000 Ordinary Lives tells the story of a series of cohort studies run in the UK. The idea is simple: follow a large sample of babies born at the same time throughout their lives. From that, we get epidemiological data (e.g. smoking is really bad for us) on , data on social inequalities (e.g. children born in poor families actually lose ground over time), whether changes in the way education or the health system matter (very much, it turns out, at the bottom of the economic scale) — and the ability to test many more hypotheses, the formulating of which could not even be dreamed of when the studies began. Of course, cohort studies are tremendously expensive, and the author shows how imperiled they have been, but the outcomes are certainly thrilling.