This monograph examines the historic attack by Adolf Hitler's Germany against the Soviet defenses in 1941. It examines actions of both armed forces to analyze what went wrong and what went right for each side. It focuses on Soviet defenses to determine the usefulness of defensive planning and operations of 1941 to today's announced policy of reasonable sufficiency and non-offensive defense. The monograph begins with an analysis of current Soviet military doctrine and President Gorbachev's stated political ideal of 'reasonable sufficiency' and his goal for the military of a doctrine of 'non-offensive defense.' The monograph continues with an examination of Soviet military theory, an historical analysis of Operation Barbarossa, and an analysis of the usefulness of the campaign for modern doctrinal development. The Soviets use historical models in the scientific development of their doctrine.