Joining insights from social science and philosophy, this book offers a nuanced view on the discourse of evil, which has been on the rise in the West in recent years. Exploring the famous 'Pear Theft' episode in St Augustine's Confessions, it looks beyond the theological implications of the event to focus instead on the secular insights that it offers when the event is placed in the context of social thought. With attention to Augustine's lengthy reflections on a seemingly marginal episode, the author contends that it is possible to discern the elements of a convincing account of intentional evil action, the Pear Theft representing a case of joint radical improvisation that lacks collective deliberation. As such, a new perspective emerges on familiar and more intuitive forms of evil in joint action that involve group identification and institutional action. Evil in Joint Action will appeal to scholars of sociology, social theory and philosophy with interests in ethics, collective action and concepts of evil.