IIRC the claim of the book is much weaker than that; his theory is that Stalin and Hitler were both building up to attack each other, each refusing to believe r

IIRC the claim of the book is much weaker than that; his theory is that Stalin and Hitler were both building up to attack each other, each refusing to believe reports from the frontline that the other side is readying to attack first. Then Hitler attacked first, literally by weeks or days, and the Soviet side, prepared for an attack, found itself utterly unprepared to defend - thus the initial success, to put it mildly, of the Third Reich.