The focus of the unfinished Book VIII is making a plan for war as a general concept cognizant of the circumstances. The main goal of this plan is to attain “the overthrow of the enemy” by destroying his army (375). The plan which has a form of strategy must be based on theory and empirical observation, as well as historical examples. War operations may appear simple, but they are not so.

Since overthrowing the adversary is “the natural end of the act of War” (376) the plan must be within the limits of this objective. Clausewitz argues that wars are “not like mutually destructive elements brought into collision, but like tensions of two elements still apart which discharge themselves in small partial shocks” (376). The state and its specifics have a direct impact on war. Because theory “is still quite powerless against the force of circumstances,” it must have room to account for all eventualities (377). The author separates theory into “where [one] can,” and “where [one] must” (377).