Hannah Arendt was one of the foremost political thinkers of the twentieth century, and her particular interests have made her one of the most frequently cited thinkers of our time. This Companion examines the primary themes of her multi-faceted work, from her theory of totalitarianism and her controversial idea of the 'banality of evil' to her classic studies of political action and her final reflections on judgment and the life of the mind. Each essay examines the political, philosophical, and historical concerns which shaped Arendt's thought, and which prompted her to become one of the most unapologetic champions of the political life in the history of Western thought.