Chapter 1 introduces the central puzzle of implementing primary education in northern India, a least likely setting for programmatic service delivery. Despite having the same formal institutions and national policy framework for primary education, implementation varies remarkably across northern Indian states. After reviewing existing explanations, the chapter outlines the main argument, anchored around variation in informal bureaucratic norms, and foreshadows the theoretical contributions to comparative politics and development. It then presents the research design and methods, based on multilevel comparisons in four Indian states (Uttar Pradesh, Himachal Pradesh, Uttarakhand and Bihar). Using multiple field research methods, I trace the implementation process from state capitals down to the village primary schools, drawing on two and a half years of field research: participant observation inside bureaucracies; village ethnography; and 853 interviews and 103 focus group discussions. I conclude with an overview of the book’s remaining chapters.