This chapter examines the planning of the German invasion of the Soviet Union. It sketches Hitler’s long-term economic and ideological motives for seeking to conquer the country, before examining the strategic considerations that determined the invasion’s particular timing in June 1941. Wehrmacht planners’ confidence was boosted by intelligence assessments that overlooked the less-than-overwhelming superiority of the German armed forces and underestimated Soviet military and economic potential. It was also boosted by their identification with the invasion’s ideological goals. Thus were the Panzer divisions and their air support, on which success depended more than anything else, committed to too many targets simultaneously, and the risk grew of a lengthy war in which superior Soviet resources would be increasingly likely to prevail. The chapter also sketches the peripheral roles played by Germany’s Axis allies in the invasion and the under-strength forces that the planners of Barbarossa would commit to rear area security. This underpowered occupation force would be compelled to cooperate closely with the SS and police in its efforts to control the occupied territories. This relationship, together with the Wehrmacht’s own ideological proclivities and harsh perception of military necessity, would help precipitate its deep involvement in Nazi crimes in the East.