This chapter describes the motivation behind and history of the Global Burden of Disease Study (GBD) and the approach it uses to measure population health. It discusses several of the value choices involved in the GBD (including choice of life expectancy, disability weights, comorbidity, and incidence vs. prevalence perspective), technical details involved in producing GBD results (including modeling techniques, data synthesis, and data analysis), several key metrics used by the GBD, and the GBD’s online data visualization tools. It concludes by briefly discussing some important empirical results from the most recent GBD study, before reflecting on the future of the GBD.