Tim Harper's 'Underground Asia' recovers the hidden history of anti-colonial revolutionaries who connected struggles across Asia through clandestine networks, shared ideologies, and practical cooperation. Harper, a Cambridge historian, traces how Vietnamese, Indian, Chinese, Indonesian, and other Asian radicals formed connections that transcended national boundaries, meeting in exile communities from Tokyo to Paris to Moscow. These networks spread not only political ideas but practical skills in organizing, propaganda, and armed resistance. Harper shows how the international revolutionary moment of the early twentieth century, when global communism offered a framework for anti-imperial struggle, shaped independence movements that would later be narrated in purely national terms. The book draws on archives across multiple countries and languages to recover figures and connections largely forgotten in nationalist historiographies. Harper is attentive to the internal contradictions of these movements, including tensions between communist universalism and national liberation that would produce conflicts after independence. Readers interested in the global dimensions of decolonization will find a richly researched account that complicates simple stories of national liberation. The lingering power of internationalist dreams, Harper suggests, continues to shape Asia's political imagination.