*Adaptation Under Fire: How Militaries Change in Wartime*

That is the new book by Lt. General David Barno and Nora Bensahel, here is one excerpt;

This emphasis on decentralized, independent battlefield actions, long a part of German military thinking, once again became a central tenet of German army doctrine in the modest force of the post-Versailles period.  Mission orders were regularly emphasized and practiced during peacetime training exercises.  moreover, the German army relentlessly critiqued the performance of its leaders and units in exercises and war games.  Commanders and staff officers at all levels were expected to do so candidly and objectively, without regard to personal embarrassment or potential career damage.  This candor extended to critiquing the performance of senior officers and higher headquarters as well.  These principles made German doctrine inherently adaptable in the face of battle.

And then a few pages later:

In stark contrast to the Germans, in the French army there was “no large-scale examination of the lessons of the last war by a significant portion of the officers corps.”  Partly as a result, the lessons that the French army drew from world War I led to a warfighting doctrine that was nearly the polar opposite of that developed by the Germans.  The French army assumed that the next war in Europe would largely resemble the last.  The staggering number of French casualties during World War I led French leaders to conclude that an offensive doctrine would prove both indecisive and prohibitively costly.  They reasoned that a defensive doctrine would best preserve their fighting power and prevent the enemy from winning another major war through an offensive strike.  As a result, nearly all French interwar thinking focused on leveraging defensive operations to prevail in any future war.

Overall, it is striking to me just how much substance there is in this book per page — a rarity to be treasured!  You can order it here.