The editors of Bridges and Boundaries asked contributors—nine political scientists and eight historians, all of them North American—to reflect on their respective disciplines and the way they go about “the study of international events” (p. 1). We should notice a positivist disposition here. While contributors “share an interest…in the state, politics and war” (p. 2), events are the stuff of international relations. That the state, politics, and war are complex institutional phenomena perhaps not reducible to events points to conceptual issues that this volume fails generally to address. Instead, contributors discuss the many problems attending generalized explanation and empirical fit—theory and science—as if their shared interests imply a common stock of core concepts.