Noting that Clausewitz is often misunderstood, Heuser's goal is to present a methodology for reading and therefore properly understanding Clausewitz. A large factor that has led to misunderstandings is the fact that Clausewitz himself learned more as life went on, and in 1827 he realized he had to totally realign his thinking to include the significant fact that war is a tool of politics/policy.
At the same time he realized that any theory of war had to account for the fact that the majority of wars were limited in nature, and not the total "ideal" wars about which he had been writing. Heuser's book does an excellent job of summarizing and accounting for the major arguments for and against Clausewitz today, and then she analyzes On War and his other writings to draw her own conclusions, which, for the most part, are pro-Clausewitz.