There is no disputing Trotsky's significance as a revolutionary. Without him there would have been no October Revolution, no Bolshevik victory in Russia's Civil War and ultimately no Soviet Union. This biography offers a new interpretation of Trotsky's career. Rather than the traditional focus on the years in opposition and exile, it concentrates on Trotsky's years in power: his pre-Revolutionary life, his role during the 1917 revolution and subsequent civil war, and his part in constructing the new Soviet state. Geoffrey Swain uses previously unexplored archival material to provide a full account of Trotsky's years in power. He examines the origin and meaning of the theory of permanent revolution and critiques Trotsky's misconceived analysis of post-revolutionary society. He goes on to assess Trotsky's claims as organiser of the October Revolution, and analyses in detail Trotsky's role in founding the Red Army. Swain also shows how Trotsky's ideas on military organisation became the basis for his vision of a future socialist society and at the same time sowed the seeds for his post-war disagreements with Lenin. The study includes an examination of Trotsky's tense relationships with both Lenin and Stalin, concluding that his continued adherence to the idea of permanent revolution meant he fatally misunderstood the nature of the struggles taking place around him.