A decent place to make a run at Foucault, this one is by far his most accessible.
Basic object of the lecture series is his "inversion of Clausewitz," i.e., the thesis that politics is the continuation of warfare by other means. I suppose the question would accordingly be whether warfare, or technique derived from warfare, is the basic engine of history, or, at least the presentation or reactivation of history.
There is very little discussion of military doctrine or military history--more significant by far is how the concept of "race war" (as distinguished from "racism" or "racist war") is a "grid of intelligibility" for historical knowledge, particularly how historical knowledge is produced and deployed in political struggle (e.g., as in the case of the "nobiliary reaction," as produced by M. Boulainvilliers--a fascinating description that covers several lectures, and is critical to a genealogy of rightwing "thought," if that is the correct term).
There's a slick reading of Hobbes, by the bye, as well as erudite commentary on Marat, and plenty of tormented critique of the ancient doctrine of sovereignty, as well as a working through the obsession with Rome (and probably becoming obsessed while doing so).
There's plenty of other useful bits thrown in along the way, via digression, but the lectures hold course against the main object, which is investigated from the 17th century through Stalinism. (The last lecture ends with some fairly amazing, if brief, commentary about the Third Reich and the Soviet Union--but, as always, he's less interested in the extremes for their own sake than for what they have in common with, and therefore how they shed light upon. the norms of his own society.)
This main line of inquiry carries the notion of "race war" through the development of the notion of "nation" to its terminus in the concept of "class," and, of course, "class struggle," which should be familiar enough. Incidentally, it's not an anti-marxist writing by any stretch, but it does have much critical commentary about socialism in general, from which marxism is only partially excepted.