This major new text provides a comprehensive, critical introduction to Leninism as an ideology. Part One presents a new and challenging account of its emergence arguing that it was frozen in the time-frame of the extraordinary war years 1914-1917. Part Two explores the inter-weaving of economics, history and philosophy in Lenin's world view concluding that, along with Marxism, it combines powerful internal coherence with fateful ambiguity towards democracy and the autonomy of politics. A detailed Guide to Lenin's Collected Works features among extensive Appendices.