With the attack of the German Eastern Army on the Soviet Union at day-break on June 22, 1941, the “most monstrous war of conquest, enslavement, and annihilation that modern history has known” began. The war on the Eastern Front ultimately devoured about twenty-seven million human lives on the Soviet side and became the scene of significant stages within the Holocaust and further unprecedented crimes in which the army played a primary role from the outset. The repercussions ultimately struck back at the invaders themselves and contributed in this way to making the Eastern Front the central theater of World War II, in which the Wehrmacht suffered its most costly and, in the end, most decisive defeats. The course set in spring 1941, which already prior to the start of Operation Barbarossa committed the German Eastern Army to the most radical and criminal waging of war imaginable, seems in hindsight all the more grave. The decision for this can be traced back to Hitler himself, who had instructed that the “crusade against bolshevism” be waged as an unlimited “conflict of annihilation.” At the same time, Hitler's demands put the Wehrmacht's conception of itself to the test. Never before had the German armed forces been issued orders, as happened shortly after, that amounted to blatant, systematic breaches of the law. It now remained to be seen whether the Wehrmacht was rightly mistrusted by the National Socialist rulers as a “gray rock in the brown tide” or not.