This book makes the case that the key to reconstructing Addams’s arguments in Democracy and Social Ethics is to approach them through the lens of late nineteenth century social evolutionary theorizing. Although Democracy and Social Ethics is now regarded as a founding text of classical American pragmatism, its evolutionary content has not been explored. This book demonstrates that in essays written during the 1890s and lightly revised for Democracy and Social Ethics Addams relies on evolutionary concepts and patterns of reasoning to develop a method of ethical deliberation with which to address her era’s social problems. Chapters 1-6 examine how Addams in the original essays employs two distinct social evolutionary frameworks, one from British Fabian socialism and the other from German anthropology. Chapter 7 examines how Addams masks these frames in Democracy and Social Ethics by substituting the conceptual categories of individual ethics and social ethics. This substitution has the effect of diminishing the intellectual power and coherence of Addams’s theorizing. The book concludes that in leaving Democracy and Social Ethics conceptually untidy, Addams produced a richer and more enduring text, one that invites her readers to participate more deeply in ethical reflection.