"Why did Churchill, so hard-headed about Hitler, maintain such illusions about Stalin’s tractability? In large part it was because the two dictators were viewed very differently in the West. In contrast with the plenitude of information available on Nazi Germany in the 1930s, the Soviet regime had remained virtually a closed book during this period. Diplomatic staff had minimal opportunity for contacts with Russian officials, let alone the ordinary population. Even ambassadors rarely met Stalin; they dealt with his foreign minister, Vyacheslav Molotov, renowned as a hard-faced “Mr. Nyet.” Moreover the Soviet press provided virtually no useful political intelligence, in stark contrast with the media in Washington, which offered endless insights into the White House and Capitol Hill. Churchill spoke aptly in 1939 of Soviet policy as “a riddle wrapped in a mystery inside an enigma.” Then suddenly the Soviets needed outside help and the doors to the Kremlin were flung open. In the second half of 1941, Roosevelt’s emissaries Harry Hopkins and Averell Harriman and Churchill’s right-hand men Max Beaverbrook and Anthony Eden all spent hours with Stalin. Churchill met him for extended summits on five occasions, joined by Roosevelt for two of them."
January 1, 1970
https://en.wikiquote.org/wiki/Vyacheslav_Molotov