How did Mussolini come to fascism? Standard accounts of the dictator have failed to explain satisfactorily the transition from his pre-World War I "socialism" to his post-war fascism. This controversial new book is the first to examine Mussolini's political trajectory during the Great War through his journalistic writings, speeches and war diary. The author argues that the 1914-18 conflict provided the catalyst for Mussolini to clarify his deep-rooted nationalist tendencies. He demonstrates that Mussolini's interventionism was already anti-socialist and anti-democratic in the early autumn of 1914 and shows how in and through the experience of the conflict the future Duce fine-tuned his authoritarian vision of Italy in a state of permanent mobilization for war.