Scholars and citizens tend to assume that rationality guides the decision-making of our leaders. Brian C. Rathbun suggests, however, that if we understand rationality to be a cognitive style premised on a commitment to objectivity and active deliberation, rational leaders are in fact the exception not the norm. Using a unique combination of methods including laboratory bargaining experiments, archival-based case studies, quantitative textual analysis and high-level interviews, Rathbun questions some of the basic assumptions about rationality and leadership, with profound implications for the field of international relations. Case studies of Bismarck and Richelieu show that the rationality of realists makes them rare. An examination of Churchill and Reagan, romantics in international politics who sought to overcome obstacles in their path through force of will and personal agency, show what less rationality looks like in foreign policy making.