This book tells the history of the International Union of Students, providing a fascinating account of a significant but understudied vehicle of internationalism amidst the Global Cold War. Focusing on three main themes; student internationalism, decolonization, and socialist transnationalism, it draws on a vast array of archival sources to explore cooperation and exchange between the Cold war's three worlds, and the role of the organization in developing global socialism. Centring Prague as a key co-ordinating centre of Cold War internationalisms and with an international focus on student organisations, Pesta contextualises the legacy and impact of student internationalism in the twentieth century. Paying particular attention to the role of 'Third World' delegates who communicated and legitimised topics such as colonialism, racism, global inequality and national liberation, it shows how the language and agenda of the IUS changed over time, and how the organization struggled to find its place after the end of the Cold War in 1989.