In the field of post-war politics this is one of the most important books that has appeared during the past quarter. It is the most extensive treatment of Bolshevik foreign policy in existence and its intrinsic value is enhanced by the fact that it is based in large measure on Russian sources. The author has had the advantage of using Russian documents and of talking with many leading Russian diplomats. Nevertheless, he does not make any effort to conceal the mistakes and failures of Bolshevik policy. His judgment on this or that question may be debated, but taken in the large this is a notable and much-needed contribution to the history of world politics.