This chapter discusses a number of events of Soviet military history, ranging from relatively minor conflicts with neighbouring states (mostly parts of the former Russian empire that collapsed in 1917) in the 1920s and mid-1930s to fully fledged participation in the Second World War. Wars with Finland in 1939–1940, Nazi Germany in 1941–1945 and Japan in 1945 are the main events that fully represent Soviet military strategy. There is still lack of access to some primary sources of key actors that shaped the Soviet military strategy in 1939–1945, so the most intensive debate in the literature has been about Stalin’s plans before and during the Second World War. Another point of discussion relates to the major failure of the Red Army during the initial phase of war with Nazi Germany, focusing on the purge of the Soviet officer corps between 1937 and 1939. In general, the war against Nazi Germany (commonly referred to in Soviet/Russian literature as the Great Patriotic War) was a struggle not only for the ‘life and death of the Soviet state’ and all the peoples of the USSR, but also for the liberation of Europe and the world from fascism.