This historical analysis of the Communist Party of Indonesia (PKI) focuses on its attempted coup of October 1965. One of the most formidable political organizations in Asia, PKI counted 20,000,000 supporters in 1965, after pursuing for 14 years a policy of collaboration with the government. The violence that erupted on October 1, 1965, with the assassination of six Army generals, climaxed the Party leadership's growing impatience with gradualism and heralded the Party's demise in Indonesia. Current evidence suggests that Party Chairman D. N. Aidit lost faith in Soviet "revisionism" and embraced Chinese Communism in 1963, after which he embarked the party on a militant course that was bound to collide with the Army, the only other significant political force in the country. Aidit engineered the October assassinations with secretly recruited collaborationist officers. Army reprisal was swift and comprehensive. Not only Aidit and his assistants, but also PKI cadres throughout Indonesia and hundreds of thousands of followers were killed in the attempted coup's aftermath. Driven underground, PKI continues to be harassed by the Army. It is questionable whether either Chinese or Soviet Communism will again be influential.