An excerpt: 

JG: What does the German decision to halt at Dunkirk tell us about what you've called "the curious command hierarchy and decision-making mechanisms of the Third Reich"?

RC: Many students of World War II still hold to a myth of German efficiency, the notion that the Wehrmacht command was infallible. The Germans had a tradition of allowing commanders a great deal of latitude while on campaign, allowing them to seize opportunities that might otherwise be lost. That tradition was responsible for a great deal of their success. But often, German commanders worked at cross-purposes with one another, requiring a strong hand on the rudder, if you will. Virtually every "blunder" attributed to Hitler in World War II originated in a conflict within the German officer corps that only Hitler had the authority to sort out.