Paul Katsafanas is Professor of Philosophy at Boston University, USA. He works on moral psychology, ethics, and nineteenth-century philosophy. He is the author of Philosophy of Devotion: The Longing for Invulnerable Ideals (2022), The Nietzschean Self: Moral Psychology, Agency, and the Unconscious (2016), and Agency and the Foundations of Ethics (2013). His recent work focuses on commitment, devotion, fanaticism, and extremism.