I was very surprised by how much in this book I found to disagree with. Heuser's analysis of Clausewitz hinges on an idealist/realist duality that she assigns to his writings pre- and post-1827, respectively, something that I'm not sure is entirely borne out by the record. The idea that Clausewitz turned on a dime and began to incorporate his later, more "realist" views about war into Book VIII and the rewrite of Book I just doesn't hold water for me, and doesn't account for the appearance of a number of "realist" insights elsewhere in the text. Heuser seems to be holding on to what I believe to be a misunderstanding of the absolute war-vs-limited war comparison on which much of "On War" turns; this is no crime on its own - many others have made the same error - but it torpedoes her thesis.
In her other writings, Heuser has shown a dogged determination to highlight Clausewitz's utter un-specialness as a strategic-/military-theoretical writer, and that determination shows through here. Yes, we know other people wrote similar things around the same time, and even before. But this book is about Clausewitz!
The real strength of this book is as a sort of literature review of the major commentaries on Clausewitz over the last two centuries, but Bassford's "Clausewitz in English" is both in some ways more thorough and, I'd hazard, more theoretically accurate (if certainly more boring for the lay reader). Heuser does a great job of opening up the untranslated German-language commentaries to the English-only reader, but I fear the really uninitiated would be led off track by her basic argument.