Is it possible for an individual leader to change the course of history? This question is as important today as it was in the past century, when "charismatic" rulers made an enormous impact, often with catastrophic consequences. In this episode, historian Ian Kershaw talks about how certain political leaders obtained and exercised power in 20th century Europe, in an effort to solve the question of the role of individual decision-makers in determining historical change. As Kershaw writes in his new book, "Personality and Power: Builders and Destroyers of Modern Europe," "the character traits of twentieth century authoritarian leaders and the structures that underpinned their rule… can perhaps at times be glimpsed in the rule of their twenty-first-century counterparts." This is not "Great Man Theory." Rather it is a timely conversation about the interplay between human agency and impersonal forces, the conditions and contexts that allow certain individuals -- democrats and dictators -- to play a decisive role, and the constraints holding them back.