Debates at world Communism’s 1921 congress reveal Lenin’s International at a moment of crisis. A policy of confrontational initiatives by a resolute minority contends with the perspective of winning majority working-class support on the road to the revolutionary conquest of power. A frank debate among many currents concludes with a classic formulation of Communist strategy and tactics. Thirty-two appendices, many never before published in any language, portray delegates’ behind-the-scenes exchanges. This newly translated treasure of 1,000 pages of source material, available for the first time in English, is supplemented by an analytic introduction, detailed footnotes, a glossary with 430 biographical entries, a chronology, and an index. The final instalment of a 4,500-page series on Communist congresses in Lenin’s time.