Political psychology applies what is known about human psychology to the study of political behavior, focusing on individuals within a specific political system. Topics such as terrorism, public support for fascism, and ethnocentrism are commonly studied within political psychology to gain better traction on the perennial question of how well citizens are equipped to handle their democratic responsibilities. The chapter provides a broad overview of the field of political psychology and introduces the topics covered in the Oxford Handbook of Political Psychology. The authors discuss the underpinnings of political behavior in broad psychological approaches such as biopolitics; personality, cognitive, and affective psychology; and intergroup relations to underscore ways in which political behavior deviates from the predictions of rational choice theory. In sum, the authors conclude that psychology provides unique and valuable insight into the dynamics of elite decision-making and mass politics.