It is 90 years since the proletarian revolution reached its tragic culmination point with the struggles of 1918 and 1919 in Germany. After the heroic seizure of power by the Russian proletariat in October 1917, the central battlefield of the world revolution shifted to Germany. There, the decisive struggle was waged and lost. The world bourgeoisie has always wanted to sink these events into historical oblivion. To the extent that it cannot deny that struggles took place, it pretends that they only aimed at "peace" and "democracy" - at the blissful conditions presently reigning in capitalist Germany. The goal of the series of articles we are beginning here is to show that the revolutionary movement in Germany brought the bourgeoisie in the central country of European capitalism close to the brink of the loss of its class rule. Despite its defeat, the revolution in Germany, like that in Russia, is an encouragement to us today. It reminds us that it is not only necessary but possible to topple the rule of world capitalism.