Matysik explores a movement known as 'ethics reform' that flourished in Central Europe between 1890 and 1930. The author examines the works of German-speaking intellectuals and activists-moral philosophers, sociologists, legal theorists, pedagogy specialists, psychoanalysts, sexual liberationists, and others-who discovered in the language of ethics a means to revitalize the public sphere. Ethics reformers used the academic field of moral philosophy to contest public- and state-sponsored rhetoric that they thought equated 'morality' with national loyalty, religious tradition, and repressive sexual mores. They founded organizations and periodicals, circulated brochures, and hosted lectures and conferences, all aimed at rethinking ethics for a secular modernity. Arising in a context sharply influenced by materialism, Darwinism, and the advent of sexology, ethics debates gradually focused on the role of sexuality in definitions of ethics and of the moral subject. Intellectuals and activists came to agree that sexuality was central to the formation of the moral subject.