What does biological evolution tell us about the nature of religion, about ethical values, or even about the meaning and purpose of life? Notable contemporary debates have indicated the continuing cultural weight of such questions. This book aims to shed new light on them by examining the significance of an early philosophical discussion of Darwin in late 19th-century Germany. It begins with Friedrich Nietzsche, whose writings stage one of the first - and still most influential - confrontations with the Christian tradition using the resources of Darwinian thought. By examining Nietzsche’s negotiation of the relationship between science and religion and showing that his appropriation of evolutionary thinking was driven by a unique existential question about the moral meaning of evolution, it complicates and critiques a standard rendition of Nietzsche’s significance for the contemporary understanding of religion. It then goes on to show how three other thinkers influential in their respective disciplines—the historian of Christian origins Franz Overbeck, the sociologist Georg Simmel, and the Neo-Kantian philosopher Heinrich Rickert—responded to Nietzsche’s “Life-philosophy” (Lebensphilosophie). Each of these critics offered cogent challenges to Nietzsche’s appropriation of the picture of evolution emerging from the biological sciences, to his negotiation between science and religion, and to the normative dimensions embedded in his concept of life. They also each offered alternative ways of making sense of Nietzsche’s unique questioning of the moral meaning of biological evolution.