(Note: I am a blog virgin, so excuse any errors in my blog manners or style.)
I assume that Clausewitz wanted generals (i.e., leaders of armies) and statesmen (i.e., leader of states with armies) to read “On War” so that they would have constructs and vocabulary with which to think and talk about undertaking a “war” in a systematic way. In Chapters 1 and 2 of Book 1, Clausewitz does much of this work by defining “What is War?” and describing its “Ends and Means”. Although Clausewitz’s definitions are clearly thought out and well stated, it seems to me that the 21th century’s global “war” experience presents some significant challenges to Clausewitz’s 19th century European definition.