It is not surprising that the functioning of the Soviet economy during the Second World War has long fascinated historians. A large literature has arisen on this topic, aimed mainly at showing how the USSR mustered the resources necessary to defeat the German war machine. The primary aim of the present chapter is not to compete with this literature, but rather to analyse the relationship between the war and the economy from the other direction – namely, to elucidate how the evolution of Soviet military doctrine helped to shape the economic system. Thus posed, the topic inevitably raises far-reaching questions concerning the flexibility of the economic system over the whole of the Stalin period. For, while the Soviets began earnestly to prepare for the war early in the 1930s, creating a central planning system that has been called a war economy sui generis, the roller-coaster evolution of Soviet military doctrine shortly before and during the war combined with the dislocations attendant upon the territorial losses of 1941–2 prompted major transformations in the economic system. Did wartime changes amount to a continuation and deepening of pre-war practices, or did they represent new departures and transformations? Were the wartime transformations harbingers of a radical reform towards a version of market socialism, a reform that could only be thwarted by virulent Stalinist reaction in the immediate post-war years?