At first glance, from a general theory perspective, Book V doesn’t offer much, focusing as it does overwhelmingly on the tactical, that is the level of warfare most open to change, most influenced by the epoch in question. Still there are various points which from a general theory perspective are worth noting.
In Chapter 2 we have the terms theater of operations, army and campaign. These corresponding to space, means and time. The means, that is the Army also need not be a state-organized force, as in the example given of the “‘army’ of the Vendée” which Clausewitz concedes is still an army. Army defined as the fighting forces representing their political community within a given theater over a certain period of time/sequence of operational/strategic events -campaign.
In Chapter 3 we see that force is a relationship, advantage is always relative, a comparison between two opposing sides. “The decisive importance of relative strength increases the closer we approach a state of balance”. Material weakness must be made up for by “the inner tension and vigor that are inspired by danger”. Clausewitz also mentions Friedrich the Great as combining vigor “with wise limitation in objectives”. This allowed for Friedrich to compensate for his relative weakness and obtain his limited political purposes against stronger foes. Finally here we see the political purpose, including even the negative one of denying the enemy his military aim, as dominating the entire process. If a state of balance only prolongs the inevitable, then vigor and tension must be brought to bare by the weaker side to upset the balance (notice the connection yet again between this chapter and Book III, Ch 18). Only by great risk can the defender hope to achieve anything like success in such a situation of inferiority. Better to go down fighting, an honorable defeat, than cowardly capitulation if only for the example it will give those who attempt to carry on the fight at a later time. Here we clearly see the Prussian patriot of 1807.
Chapter 4 with its explanation of the relative merits of cavalry, infantry and artillery nevertheless presents the general theorist with some abstractions worthy of consideration: the character of war is modified by the predominance of one of its arms; the view that the composition of armies reflects the political organization that brings them into being and controls them, this can even include political power relationships among the elite as in the Middle Ages; and finally Russia and Austria, for example, are included in this direction [maintaining large numbers of cavalry] because they still maintain fragments of Tartar institutions in their political structures. What could Clausewitz mean by this sentence? Here we have a very important confirmation of Clausewitz’s theory of politics, along with his concept of cohesion, which I mentioned as one of the types of theory presented in On War. I will explain this in detail when we get to Book VIII.
Chapter 5, of course, should be given special consideration when considering how many guys back during the Cold War dedicated their professional lives to the study of Warsaw Pact Order of Battle. Almost everybody had a copy of On War on his bookshelf, having given the text a go on one level or another. The last paragraph of this chapter should be the basis of the study of adversarial order of battle.
I could go on, but I think you get the idea.
On to Book VI!