The aim of this research program is to analyze long-term demographic processes connected to industrialization, modern economic growth and the profound societal transformation of the 20th century. These changes have completely altered living conditions across the developed world, not only in terms of nutrition, consumption and overall quality of life, but also in loosening many of the demographic constraints that dominated people’s lives for so long. The broad outline of these processes is well known through research at the macro level but we still know very little about the micro-level foundations, which is of great value to fully understand and explain the processes. Within the Landskrona Population Study (LPS) we study these vital economic and demographic changes in Sweden through the lens of an industrial city which has experienced this transformation. The LPS is based on a unique data infrastructure, the Scanian Demographic Database, containing economic and demographic longitudinal data at the individual level for the full 20th century (ca 350,000 individuals). It focuses on four fundamental and interrelated economic-demographic processes: (1) Inequality in health and mortality, (2) Changing family patterns and gender relations, (3) Social and economic mobility, and (4) Immigration and integration.