Book excerpt: Stalin’s Red Army entered World War II as a relatively untried fighting force. In 1941, with the launch of Operation Barbarossa, it joined battle with Hitler’s army, the most powerful in history. After a desperate war of attrition over four years, the Red Army beat the Nazis into defeat on the Eastern Front and won lasting fame and glory in 1945 by eclipsing the military might of the Third Reich. This book begins with a review of the historical background of the Red Army in the years leading up to the outbreak of war in 1939, and follows with a discussion of the major themes in the development of Soviet forces during the "Great Patriotic War" that ensued in 1941. The Red Army’s organizational structures are examined, from high command down to divisional level and below; Soviet combat arms and weaponry are also described in detail.