We are entering the centenary of the revolutionary upheavals which convulsed Europe and Asia in the wake of the First World War. Sustained by those upheavals, a new left emerged grappling with the daunting challenges of trying to create an alternative to capitalism and war. John Riddell's three decades of effort to make available the proceedings of the First Four Congresses of the Communist International (Comintern) are part of a new generation working to make available to an English speaking audience some of the key disucssions and deliberations of the left in that era. His latest volume – "To the Masses" – surveying the discussions of the Third Comintern Congress completes this work. Focussing on the united front – what a contemporary left would call "coalition building" – the book is an invaluable resource both to our understanding of this period, and to the challenges our new left faces in the still ongoing struggle against capitalism and war.