The fourth volume is devoted to the most important military and political events of the Second World War, which took place since June 1941. by April 1942. The main ones were the aggression of fascist Germany against the USSR and the disruption of Hitler's "lightning war" plan by the Soviet people and its armed forces. At the end of 1941[edit] military operations began in the Pacific basin and in Southeast Asia. The United States of America entered the war. The volume discusses in detail the mobilization of economic and human resources of the belligerent states and the deployment of their military and economic potentials. In this connection, the picture of the movement of the productive forces of the Soviet country from the western regions to the east, unprecedented in the history of wars, the greatness and significance of this feat of the Soviet people for the further conduct of the war, is revealed. A large place in the volume is occupied by the most important problem of creating an anti-Hitler coalition .. The paper explores the problem of organizing and conducting strategic defense in the conditions of incomplete deployment of armed forces to repel the first blows of the aggressor.