The 1958 National Child Development Study (NCDS) follows the lives of 17,000 people born in England, Scotland and Wales in a single week of 1958. The National Child Development Study started in 1958 as the Perinatal Mortality Survey. Sponsored by the National Birthday Trust Fund, the survey was designed to examine the social and obstetric factors associated with stillbirth and death in early infancy among the children born in Great Britain. By collecting information on various aspects of life, the NCDS has become an invaluable data source on such diverse topics as effects of socioeconomic circumstances on health, social mobility and changes in social attitudes. Today, the 1958 cohort is one of the best resources for understanding how retirement and ageing are changing in Britain. With quantitative and qualitative, social and biomedical data, the 1958 cohort is a leading resource for both policy development and best practice in longitudinal research. Study website: www.cls.ucl.ac.uk/cls-studies/1958-national-child-development-study/