This article addresses the role of the workforce in achieving health goals in developing country contexts. It reviews the health economics and health systems literature on the health workforce. It organizes the review according to three perspectives on health workers, which correspond roughly to chronological phases of academic publication: health workforce planning, the health worker as economic factor, and the health worker as necessary resource. This article describes the health policy backgrounds that led to each phase of research and then reviews relevant literature. However, the perspectives are useful in framing past research, structuring our exposition, and laying out a research agenda on the health workforce for coming years. It further discusses opportunities for future research on the health workforce abound and suggests that the transfer of existing approaches could lead to important insights.