When wars are declared or avoided, crises created or resolved, or peace and cooperation flourish instead of destruction and terrorism, diplomats, journalists and the public often explain them as resulting from personality (and other psychological) characteristics of individual actors. Academic analysts, however, are trained in situational, structural, and historical perspectives and thus are skeptical of such explanations. After all, without the German defeat in World War I and the later support of rich industrialists, Adolf Hitler might well have remained a failed artist, living in poverty in Vienna. Even his racial policies echoed themes common in 19th-century German thought. On the other hand, Robert Kennedy once remarked that during the 1962 Cuban Missile Crisis, US President Kennedy’s close advisors were “bright, able, dedicated . . . probably the brightest kind of group that you could get together under those circumstances”; then adding ominously that “if six of them had been President of the US, I think that the world might have been blown up.” Systematic academic study of leaders’ personalities and foreign policy charts a course between these two perspectives: in novel, ambiguous, complex, unstable, or conflicted situations, leaders can have important effects on foreign policy processes and outcomes—through their goals, impulsivity versus thoughtfulness, styles of seeking and interpreting “information,” and emotional responses to symbols. The psychological concept of “personality” includes several different kinds of “variables” or dimensions of individual difference: traits or consistencies of style; cognitions or beliefs, values, cognitive complexity, heroes, and self-concept; motives or goals conscious and nonconscious (or implicit). Underlying these three aspects of personality, however, are social contexts (culture, social class, history, gender, family structure, religion, institutions), which reflect past influences on personality development and present channels through which the other aspects are expressed. Since political leaders are not usually available for assessment with the usual tools and instruments of personality psychology, analysts must rely on alternative techniques, such as psychologically oriented interpretations of known biographical facts, systematic content analysis of verbal or written texts (speeches, interviews, written works, etc.), or assembling pooled judgments of experts or historians. Many of the case studies and more systematic research cited in this bibliography focus on leaders’ personalities rather than their foreign policies. Armed with an understanding of the elements of personality, however, researchers can readily extrapolate from the research literature to understand and predict foreign policy behaviors.