The German expression "Das F? hnlein der vier Aufrechten" is difficult to translate into Russian. It means: "A detachment (or a small battle group) of four stalwarts." So she named herself and her friends Clara Zetkin in 1919, when Karl Liebknecht, Rosa Luxemburg, Franz Mehring were no longer alive, when she was left alone from the "four stalwarts." What united these people, singling them out in the ranks of the German Social Democrats, in the party in which they operated for many years? One thing can be answered: they were revolutionaries. When, at the turn of the century, there was a danger that German social democracy, at the cradle of which Marx and Engels stood, would turn into a party of social reforms, they firmly took a position on the left flank. The political struggle for the interests of the proletariat, for socialism is the main business of the life of these people, who are deeply convinced that it is possible to go towards this goal and achieve it only under the flag of the International.