This chapter describes the data collection strategy and multimethod research design employed to test the theory in the subsequent chapters of the book. The structure of the empirical analysis mirrors the book’s primary argument: to show how peacekeeping works from the bottom up, from the individual to the community to the country. Given that UN peacekeepers deploy to the most violent areas, the design needed to account for selection bias as well as other confounding variables in order to make causal inference possible. Using data from individual- and subnational/community-level data from Mali as well as cross-national data from the universe of multidimensional PKOs deployed in Africa, the book employs a three-part strategy to test the hypotheses in the next few chapters. First, the book considers the micro-level behavioral implications of the theory using a lab-in-the-field experiment and a survey experiment, both implemented in Mali. Second, it test whether UN peacekeepers’ ability to increase individual willingness to cooperate aggregates upward to prevent communal violence in Mali. Third, the book considers whether these findings extend to other countries.