In March 1946, a group of British scientists recorded the birth of every baby in the country in one particular week with the goal of studying their lives as they unfolded. The study still runs and it has become, as it happens, a continuous insight, from cradle to grave. Throughout the years and the decades, these dedicated scientists, for the most part anonymous to the world, have put under the microscope these men’s and women’s birth, childhood, education, marriage and work, and now, that they are approaching the sunset of their lives, how they are coping with old age. Throughout commonalities—educational shortcomings, for instance, were shocking to discover, as well as health conditions such as obesity and cholesterol—one common pattern emerged: social class, or where we stand in terms of income and opportunities already at birth, has a major impact in determining the path our lives follow. It was startling to note that those born in 1958 had a better shot at social mobility than the 1970 class. The study has helped shape British government policies to remedy some of these inequalities.