Amadeo Bordiga was one of the greatest figures of the Third, or Communist, International. His formidable body of writings remains energizing, instructive, and often surprisingly topical today. The Science and Passion of Communism presents the battles of this brilliant Italian communist in the revolutionary cycle of the post-WWI period, through his writings against reformism and war, for Soviet power and internationalism, and against fascism, on one side, and Stalinism and the degeneration of the International, on the other. Equally important was his sharp critique of triumphant U.S. capitalism in the post-WWII period, and his original re-presentation of the Marxist critique of political economy, which includes the capital-nature and capital-species relationships, as well as a programme of social transformations for the revolution to come.