If you want to understand the context behind all other books on military strategy written since Clausewitz (any book written in the last hundred years), you must read Clausewitz. If you want to understand why the US Army was so dead set on failing to anticipate the next war and continued to train for symmetric war until very recently, you must read Clausewitz. If you want to understand why the new Army and Marine Corps Counterinsurgency Field Manual written by General Petraeus, Lt General Amos, and Lt Colonel Nagl is so celebrated, you must read Clausewitz. You should also read Petraeus et al's Counterinsurgency Field Manual. The difference in tone and scope is staggering. If you want to understand military strategy going forward, you must understand Petraeus's book. I assure you, it is on the nightstand of the President and every military officer (and not because it says that on the cover, but because I'm one of them). If you are running a startup, read the Petraeus book as though you are the insurgent. If you are at MSFT or Google, read it as though you are in the US Army.
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