Status Updates From Slaughter on the Eastern Fr...

The Red Army's brilliant victory at Stalingrad was won largely because they did not attack the German's strengths, but their weaknesses: the allied Axis armies of Romania, Italy and Hungary. All of whom were routed, trapping the Germans in the Stalingrad pocket.

With Britain defiant, the US clearly looking for an excuse to enter the war, and with even fairly optimistic intelligence appraisals highlighting the enormity of the proposed task, Hitler was adamant about invading the USSR.
What made this worse was his vague inability to define goals.

This particular accounting of the battles in Mongolia against the Japanese in 1939 is significantly different than previous works I had read. Possibly newer research has effect on the structure of the narrative.
The air campaign in particular was illuminating.