This Policy Brief is an outcome of the UNU-WIDER research project ‘Social Development Indicators’. The overall aim of the project was to provide insights into how human well-being might be better conceptualized and, in particular, measured, by reviewing various concepts and measures and then offering recommendations for future practice and research. This Policy Brief outlines a contextual background to the project, by introducing some key concepts and measures used in assessing achieved well-being, especially at the national level. Highlighted are some of the best known and most widely used well-being measures. The Policy Brief then provides an overview of the five edited volumes that have emerged from the project, summarizing some of the main conclusions.