Slawomir Debski's book presents a brilliant reconstruction of the sequence of events from the point at which Germany clinched its rapprochement with the Soviet Union in August 1939 until the open clash of the two totalitarian Powers in June 1941. His book answers key questions about the motives that prompted Hitler and Stalin to reach a deal and the reasons why their alliance collapsed. Debski offers his readers a set of novel and thoroughly thought-out assessments, with an original account of diplomatic relations between the Third Reich and the Soviet Union in 1939-1941, based on his examination of German, Soviet, and Polish sources. The study is an invaluable source of information for all who are interested in geopolitics, the background to twentieth-century diplomacy, and the history of totalitarian states. This book will give readers a deeper insight into the plight of the Polish State and its people, wedged between the two twentieth-century totalitarian regimes.