The British feminists Kathleen Courtney, Catherine Marshall, and Helena Swanwick played leading roles in two of the most significant movements of the twentieth century: the fight for the emancipation of women and the struggle for peace and justice among nations. This book describes the developing political consciousness of these women and demonstrates how they helped to organize British women to lobby for their enfranchisement during the Edwardian and prewar periods and how, throughout the Great War, they defended civil liberties and campaigned for a negotiated peace and a system of international government. After the war, they were dismayed by the failure of the Treaty of Versailles to implement the principles of Wilsonian internationalism and joined with others to educate the public in these principles as a means of securing a permanent peace. This book documents how they worked for revision of the peace treaty, disarmament, and a strong League of Nations. The author argues that throughout their careers, the ideas and activism of these women were guided by a belief in liberty, equality and justice, as well as the necessity of applying reason to gender relations and international politics.