This project presents a new data set that can be used for describing long-term social and demographic change in the Netherlands. The data set is based on harmonized surveys previously collected by the Netherlands Institute for Social Research (SCP) and Statistics Netherlands (CBS) from 1979 to 2022. Differences in measurement and design are discussed, harmonization procedures are explained, and the data file with common variable names and value labels is documented. The code is publicly available allowing researchers to obtain the harmonized data (in a companion paper). Detailed tables are presented for all characteristics in the harmonized data set, both for the entire population 21+ and for the working-age population 21-64. The data set provides descriptive information that is often missing or incomplete in register data and retrospective surveys.