I keep returning to this book as among the best I've ever read. It is both good reading as military history and failure analysis: no one has been able to write so deftly and originally about why France fell so swiftly in 1940. Unlike other military history books, this one is not heavy on maps nor units nor armament, merely a very incisive and friendly discussion of why France fells so quickly.
Serving in both WW1 and WW2, he points a litany of reasons why the French army, which was better equipted than the Germans, collapsed so suddenly. Despite what I learned in highschool about the French defeat of WW2 (France was overconfident in the Maginot Line), Marc Bloch tells a different reason. The French army, aside from its reliance on the Maginot Line, failed to anticipate how modern weapons shortened space. The French army never understood how the speed of modern weapons had shortened space. Marc Bloch, serving at the front in 1940, recalled that the German offensive actually seem to overtake each French retreat: whenever Marc Bloch's unit retreated in 1940, they constantly found the Germans in their rear. The consequence was the French army was in a perpetual retreat and lacked the time to mount a proper counter offensive.
Marc Bloch also points to the cultural factors in the French defeat, namely the French education system which ignored history and visual arts in its cirriculum. He proposes a greater emphasis on both. I agree with the latter: in the US, we are saturated with images but we are visually illiterate. As for history, there is now too much emphasis on history without a comparable attempt to work things out in the present. This is a terrific book that reads like a no-holds barred fight.