This is a translation of "Seconda Guerra mondiale - conflitto imperialista su entrambi i fronti contro il proletariato e contro la Rivoluzione." A work, whose publication in Italian occupies the whole of issue 40 of the journal Comunismo. Besides showing how the war was an anti-proletarian phenomena, it exposes, with direct quotes, the fact that WW2 was led to exterminate and beat down workers: Little known facts such as how the Allies, during the "liberation" of Italy, led bombing runs of working class neighborhoods in order to demoralize revolutionary spirited workers. The information here is staggering: The fraternization of Wehrmacht troops with Italian workers; the struggle of the Stalinist PCI against fraternization by means of the same shameless and disgusting racism that all the other Stalinist parties engaged in during the war. Why did troop fraternization fail during WW2 to a much bigger extent than in WW1: this work explains it. It was the Resistance, using calculated terrorist attacks to divide Italian workers from the uniformed German workers. The myth of everything the bourgeois left holds dear about the second World War is torn apart in this work. The documentation of the activities of the Italian Communist Left during the war is an important weapon for it shows how ours was the only Party that did not fall into non-Marxist opportunism.