What characterised women's international co-operation in the interwar period? How did female activists from different countries and continents relate to one another? Marie Sandell here explores the changing experiences of women involved in the major international women's organisations - including the International Council of Women, International Alliance of Women, Women's International League for Peace and Freedom, and the International Federation of University Women - as well as the changing compositions and aims of the organisations themselves. Moving beyond an Anglo-American focus, Sandell analyses what the term 'international sisterhood' meant in this broader context, which for the first time included women from the beyond the Western world. Focusing on shifting identities, this book investigates how notions of 'sisterhood' were played out, and contested, during the interwar period and will be invaluable reading for scholars of women's history and twentieth-century world history.