The West of Scotland Twenty-07 Study is a population-based multi-cohort study which has followed three cohorts of men and women in the West of Scotland across twenty years. Set up in 1986, the study was designed to investigate the differences in health by socio-economic circumstances, gender, the place where people live, age, ethnic group and family type. Through tracking three cohorts of volunteers, each born roughly twenty years apart, the study provides data at critical points in the lifespan, as participants make the transition from adolescence to working life; through the main part of working life; and from working life to retirement. Additionally, the study was designed to explore the effect of the historical context of people’s lives on their health and circumstances by comparing the different cohorts at the same age at different points in time.