Analyzing many events and phenomena that occurred in the leading countries of the world, and, first of all, in Russia, before, in the course of, and after World War I, the author raises and explores a number of problems of that time which are still urgent today and connected with international and domestic security of Russia. Key words: World War I, Russia, imperial nationalism, ambitions of political elite, international relations, overthrow of monarchy, war lessons, consequences of the Versailles Treaty.