That conflicts with the dry, boring, but extremely enlightening account written by Hans Ulrich Rudel, based on some of the first Luftwaffe recon flights to occur into the USSR after the onset of Barbarossa. It was evident based on the staging of materiel, men and fortifications (or lack thereof), that Stalin had been readying a serious offensive along two alignments - along the Danube Corridor, and, along the Moscow-Berlin one. Stalin's biggest mistake was his underestimation of the ability of the materiel deficient Germans to take Blitzkrieg to a whole new level, penetrating deep into the USSR with minimal to non existent logistical support. Of course, ultimately, the Nazis were forced to retreat or were simply cut off and destroyed since their hastily assembled offensive was unsustainable. So in the end, Stalin's lack of preparations for a defensive war, in favor of his preps for a major breakout into the heart of Europe, was not an ultimate disaster. No one can invade Russia without amazing logistics and hope to succeed. In the end, Stalin's push Westward was only really delayed by 18 months.