During the 1950s and first half of the 1960s the Indonesian Communist Party grew from a few thousand members to become the third largest communist party in the world, before it was annihilated in a violent purge in 1965-6 that saw perhaps half a million alleged communists killed. Whilst a growing body of scholarship has analysed the anti-communist violence of 1965-6, much less has been written about the Party's experience and significance in the preceding decade and a half. Communism, Cold War, and Revolution: The Indonesian Communist Party in West Java, 1949-1966 is the first major study of the Party during that period to be written since the end of the Cold War. The book examines the Party's development at the intersection of world communism, a global Cold War and Indonesia's revolution. It shows that the Party represented both a revolutionary organisation and a vibrant movement, which was both linked to international networks and deeply intertwined with Indonesia's social fabric. In this book, Matthew Woolgar introduces the term 'archipelagic communism' to encapsulate the ability of the Party to achieve impressive growth amid a growing pluralism in global communism and a context of extreme local cultural and social diversity. Woolgar takes the case study of West Java - a populous and diverse province, which had a substantial communist presence - as an entry point for examining these developments. The study draws on a wide array of sources, ranging from interviews and government documents to newly available Party archives, to recreate Party life in unprecedented depth. The study traces the dialogue that communist leaders engaged in with foreign comrades but also argues that key to the Party's growth were activist energies at the grassroots and the Party's efforts to navigate social, cultural, and ethnic cleavages within Indonesian society. It shows how the Party became entangled with trade unionism, land conflicts, struggles for women's rights, youth activism, and cultural activities. It also delineates how conservative elites, backed by Western governments, used counter-revolutionary violence to destroy the Communist Party and institute a wide-ranging reshaping of Indonesian society: removing labour rights, reversing land reforms, enforcing a patriarchal state ideology, and reinforcing markers of ethnic and religious difference.