During the ten years preceding this book's publication in 1984, a good deal of material on Britain's role in Allied relations during the Second World War had become available at the Public Record Office in London. Little of this documentation, however, had yet been published: the series 'Documents on British Foreign Policy' stopped with the outbreak of war in September 1939; there was, therefore, no British equivalent to 'Foreign Relations of the United States' for the war years. This book fills this void, using a selection of documents to illustrate one of the most important themes of British wartime diplomacy: relations with the Soviet Union. Until the publication of this book the interested student or researcher had to be prepared to spend long periods delving into the files of the Public Record Office, or else rely on secondary material.