Communism. Hillgruber saw Hitler's foreign policy program was totally unrealistic and incapable of realization. Hillgruber argued that Hitler's assumption that a German "renunciation" of naval and colonial claims, in exchange for British recognition of all of Europe as lying within the German sphere of influence, was based on an unviable notion that British interests were limited only to the naval spheres and spheres outside of Europe. Hillgruber noted that Britain was just as much a European as a world power, and would never accept so far-reaching a disruption of the balance of power as Hitler proposed in the 1920s in Mein Kampf. Hillgruber wrote that Neville Chamberlain for all his attachment to appeasement, once he learned that Hitler's aims were not limited towards revising Versailles, ultimately went to war with Germany in September 1939 rather than accept the disruption of the balance of power that Hitler was attempting to carry out". Likewise, Hillgruber argued that Hitler's contempt for the Soviet Union, especially the fighting power of the Red Army, was a dangerous illusion. Hillgruber argued that the lack of British interest in Hitler's proposed anti-Soviet alliance temporarily derailed Hitler's foreign-policy programme in the late 1930s, and led to the ideas of the Foreign Minister Joachim von Ribbentrop, whose anti-British foreign policy programme Hillgruber called the "very opposite" of Hitler's taking precedence in the period 1938-1941 In a 1967 review, the American historian Howard Smyth called Hitlers strategie "a magnificent work based on a thorough study of all source material and literature available in German, English, French, and Italian, and on translations from Russian and Japanese". The German historians Rolf-Dieter Müller and Gerd R. Ueberschär wrote that Hitlers Strategie was ...a book that became the standard work and still retains most of its validity. Despite vehement criticism by some of his older colleagues, Hillgruber undertook a somewhat new interpretation of Hitler's foreign policy in this doctoral thesis...The chief aim of Hitler's foreign policy, imbued with notions of racial superiority, was to conquer a new Lebensraum in the east and achieve a position of world dominance...This interpretation of Nazi foreign policy clearly differed Hillgruber from Fabry and other revisionists, and his work held up well enough to be reprinted twenty years later with only minor changes. Hillgruber argued that Hitler drew a distinction between winning Germany a Grossmacht (great-power) position through Kontinentalimperium (Continental imperialism) and the goal of Weltmacht ("World Power") where