Leon Trotsky, whose role in the founding of the Communist International was second only to Lenin's, was also the principal fighter against its degeneration. After Lenin's death he battled to reverse the disastrous course on which it was being directed by Stalin and Bukharin, with their theory of 'socialism in one country'. Trotsky's devastating criticism of this theory and the policies flowing from it, written for the Sixth Congress of the Comintern, forms the main part of his book. More than just a defence of the principles of Bolshevik internationalism and the lessons of the first four Congresses of the Comintern, it is an important and independent contribution to Marxism. Trotsky examines every aspect of the Comintern in the four years after Lenin's death: its programme, strategy and tactics, organization, and the internal life of the Soviet Communist Party itself. Included in this new edition - for the first time in English since 1929 - is an article giving brief character-sketches of the leading Comintern functionaries.