Clausewitz was among those intrigued by the manner in which the leaders of the French Revolution, especially Napoleon, had changed the conduct of war through their ability to motivate the populace and to gain access to the full resources of the state; thus unleashing war on a greater scale than had previously been seen in Europe. Clausewitz was well educated and had strong interests in art, history, science, and education. He was a professional soldier who spent a considerable part of his life fighting against Napoleon. The insights he gained from his political and military experiences, combined with a solid grasp of European history, provided the basis for the book.
The book contains a wealth of historical examples used to illustrate its various concepts. Frederick II of Prussia (the Great) figures prominently for having made very efficient use of the limited forces at his disposal, though Napoleon is perhaps the central figure.
According to Azar Gat, the "general message" of the book was that "the conduct of war could not be reduced to universal principles. Among many strands of thought, three stand out as essential to Clausewitz's concept:
• War must never be seen as having any purpose in itself, but should be seen as an instrument of Politik--a German word that conflates the meanings of the English words policy and politics: "War is not merely a political act, but also a real political instrument, a continuation of political commerce, a carrying out of the same by other means.").
• The military objectives in war that support one's political objectives fall into two broad types: "war to achieve limited aims" and war to "disarm” the enemy: “to render [him] politically helpless or militarily impotent."
• All else being equal, the course of war will tend to favour the party with the stronger emotional and political motivations, but especially the defender (a notion that surprises and confuses many readers, who typically expect a soldier—especially a German soldier—to be a proponent of aggressive warfare).
