This paper explores the centrality of exchange in James Buchanan’s research program, which is crucial for understanding his contributions to political economy. For Buchanan, focusing on exchange provides a distinct analytical framework—the “exchange paradigm”— for studying and understanding the world. The exchange paradigm emphasizes that the study of social life is grounded in the purposeful behavior of individuals who must cooperate with others in two ways. First, people must coordinate with others to create rules that facilitate cooperation in future periods. Second, people must then coordinate with others within existing rules to achieve their goals.