Born in Vercelli in 1861, Luigi Galleani is considered, with Errico Malatesta, the most influential militant of Italian-speaking anarchism. A tireless thinker, agitator, and public speaker, he attracted large numbers of workers to the revolutionary cause in Italy and the United States. This book, the result of a fruitful collaboration between Antonio Senta, a scholar of anarchist history, and Sean Sayers, a philosopher and Galleani's grandson, is the biography of one of the most charismatic exponents of workers' struggles in Europe and the United States between the nineteenth and twentieth centuries.