On the outbreak of war in 1914, the Western Front soon bogged down in the stalemate of trench warfare. On the Eastern Front, things were very different. The three great Continental empires, Germany, Austria-Hungary and Russia, became locked in a deadly struggle involving rapid advances by mobile infantry and massive cavalry battles.

Little known to Western readers, this campaign determined the fate of Europe and much of the world for the rest of the century. All three empires exhausted themselves and collapsed in 1918. The Russian collapse led directly to the rise of Communism, the German collapse to Fascism, and the Austrian Empire dissolved into numerous unstable states such as Czechoslovakia, Hungary, and Yugoslavia, whose status and boundaries are still causing violent conflicts today.