Seeing how high was Napoleon's opinion of Jomini as a master of the science of war, it is curious how his views on the two natures of wars have been ignored in the present day. It is even more curious in the case of Clausewitz, since we know that in the plenitude of his powers he came to regard this classification as the master-key of the subject. The explanation is that the distinction is not very clearly formulated in his first seven books, which alone he left in anything like a finished condition. It was not till he came to write his eighth book _On War Plans_ that he saw the vital importance of the distinction round which he had been hovering. In that book the distinction is clearly laid down, but the book unhappily was never completed. With his manuscript, however, he left a "Note" warning us against regarding his earlier books as a full presentation of his developed ideas. From the note it is also evident that he thought the classification on which he had lighted was of the utmost importance, that he believed it would clear up all the difficulties which he had encountered in his earlier books--difficulties which he had come to see arose from a too exclusive consideration of the Napoleonic method of conducting war. "I look upon the first six books," he wrote in 1827, "as only a mass of material which is still in a manner without form and which has still to be revised again. In this revision the two kinds of wars will be kept more distinctly in view all through, and thereby all ideas will gain in clearness, in precision, and in exactness of application." Evidently he had grown dissatisfied with the theory of Absolute War on which he had started. His new discovery had convinced him that that theory would not serve as a standard for all natures of wars. "Shall we," he asks in his final book, "shall we now rest satisfied with this idea and by it judge of all wars, however much they may differ?"[2] He answers his question in the negative. "You cannot determine the requirements of all wars from the Napoleonic type. Keep that type and its absolute method before you to use _when you can_ or _when you must_, but keep equally before you that there are two main natures of war."