Mario Tronti was the principal theorist of the radical political movement of the 1960s known in Italy as operaismo and in the Anglophone world as Italian workerism, a current which went on to inform the development of autonomist Marxism. His “Copernican revolution”—the proposal that working class struggles against exploitation propel capitalist development, which can only be understood as a reaction that seeks to harness this antagonism—has inspired dissident leftists around the world. Tronti’s influence as a theorist thus already reaches far beyond Italy to activists and writers working in different sectors on different problems historically and geographically. While his imposing and acclaimed Workers and Capital has only recently appeared in English translation, Tronti has influenced many of the most creative social and political theorists of our time. Antonio Negri and Michael Hardt have long acknowledged the influence of Tronti on their thinking, drawing especially on his inversion of strategy and tactics in their influential collaborations. Tronti’s work in the 1960s also furnished important building blocks for a Marxist feminist critique of unwaged labor—as developed by Mariarosa dalla Costa, Silvia Federici, and many others working on social reproduction theory—as Tronti showed how capitalist control extends beyond the factory to all of society. Fred Moten and Stefano Harney have echoed Tronti’s calls for a radical antagonism “within and against” institutions and the state. ‘The Weapon of Organization’ is a crucial introduction to Tronti, presenting a variety of never-before-translated texts—personal letters, public talks, published articles. With an incisive and provocative introduction that situates Tronti and highlights his relevance to contemporary political struggle, Anastasi translates and restores key writing from the birth of Italian operaismo—days of street fighting and theorizing for a renewed age of revolution. Tronti’s goal, Anastasi writes, was not to become a revered thinker but to participate in the destruction of capitalist society.