Taking Muzaffar Ahmad's early career (1913-1929) as its chronological frame, this book examines the dialectical interplay between his social being and the wider social consciousness which made him arrive at communism, in vital conjunction with the sources of self transformation in the city. 1929 marked the end of the first phase in his political life as a pioneer of the communist movement as it had emerged in Bengal and India of the 1920s. This was the year when leading communists were arrested and the Meerut trials began. The biographical details of Muzaffar Ahmad between 1913 and 1929 converged with a significant phase in the social and political history of India and the world. These years can also be read as two crisis-points in the history of imperialism and capitalism: 1913, the eve of the First World War, and 1929, the year of the Wall Street Crash which set off the Great Depression; a period within which socialist ideas and communist activity became politically familiar in different parts of the globe. Many socially alienated, economically distressed and politically dissatisfied urban intellectuals stood at the crossroads of established and radical identity-formations. A 'fraction' emerged, informed by working class protest from below, and the leftward turn in literary and cultural fields. They were moving away from the more established political routes open to those from their social background to combat colonialism, and identifying with a more radical vision of decolonization. The little investigated history of the left in Bengal before the Meerut trials, and the convergences between individual radicalization and a new political space in the city are unraveled by tracing this process, in the context of colonial Calcutta and through Muzaffar Ahmad's transitions. This monograph will interest those engaged with the histories of communism, port-cities, Bengal Muslims, workers, intellectuals, migration, colonial intelligence, and internationalist currents.