This book has been in preparation for nearly a decade. In 1986 Mary McAuley invited me to present a paper on the comparative economics of World War II to the annual conference of the National Association for Soviet and East European Studies in Cambridge the following spring. Trying for the first time to arrive at well-founded comparisons among Germany, Britain, the United States, and the Soviet Union brought home to me how inadequate were existing measures (mostly based on official statistics) of the Soviet war effort. After hearing my paper, Peter Wiles introduced himself to me, giving me to understand that he approved intensely of what I had done, while at the same time disbelieving it completely. From that moment I was drawn inexorably into a task which has lasted twice as long as the war which provided its subject.

The whole thing would have been impossible without the work of Abram Bergson and others in the two postwar decades, sponsored by the RAND Corporation of the United States Air Force. I am grateful to Bergson himself, and also to his former collaborators Janet Chapman and Lynn Turgeon, for their recollections, advice, and comments.

One of the features of western independent evaluations of Soviet economic progress was always the creative tension between American can-do and British scepticism. More recently, Russian economists have joined the fray.