The article is clearly sensationalist. I'm not saying the implication is wrong, I'm saying the article can't prove it. I expect the book won't contain precise source references either. Other books on the same topic have been criticized for unclear sources, as well. The endorsement by the person who inspired the author in the first place is not an independent opinion and thus clearly biased.
> At a company called Temmler in Berlin, Dr Fritz Hauschild, its head chemist, inspired by the successful use of the American amphetamine Benzedrine at the 1936 Olympic Games, began trying to develop his own wonder drug – and a year later, he patented the first German methyl-amphetamine.
So, it was initially developed by the Allies. It's fair to assume they used it, too.
> Was Blitzkreig, then, largely the result of the Wehrmacht’s reliance on crystal meth? How far is Ohler willing to go with this? He smiles. “Well, Mommsen always told me not to be mono-causal. But the invasion of France was made possible by the drugs. No drugs, no invasion.
Under the assumption that the Allies used stimulants, too, there is no advantage?