Worst military mistakes.

[Meothar]

Utterly false. In late 1917, the Germans had won the Ukraine Breadbasket, so their food situation was stable. Verdun had no effect on the German Army, as a matter of fact the Germans did win Verdun. They reduced the French to a few fortifications while they took all the Strategically vital ground and accomplished their objectives.

I suggest reading Myth of the Great War by John Mosier and follow it up with the sources he provides.

The book you mention is not unchallenged because of the onesided position the author takes. And sources in wartime are always filled with propaganda.

Verdun was not a victory for Germany but an offensive that failed to reach the goal (Verdun) and was repelled. In the end, both sides have lost an equal number of soldiers and no advantage. Without intervention of the USA, Germany would perhaps been able to delay the end of the war until 1920 or such, but no chance for winning.
But I think it's not the right place to discuss this. WW1 was one big military mistake.