Carl Philipp Gottfried von Clausewitz died almost 200 years ago, yet he remains one of the most important and influential of all military thinkers. His teachings combined strategy with military knowledge to produce a dialectic approach to the philosophy of warfare, and his work is still widely taught in military academies around the world. There are few senior military leaders anywhere who are not familiar with his seminal book, On War.

In fact, with the exception of Napoleon Bonaparte, no man was more influential on the military tactics and strategy of 19th century warfare than Clausewitz, a Prussian soldier and military theorist who stressed the moral and political aspects of war. On War was mandatory for all military students and officers to read during the 19th century, and it was common practice for generals during the American Civil War to carry Clausewitz’s treatise and read it to assist them in strategy and tactics.

On War covered every conceivable facet of warfare, using historical battles as examples of what to do and what not to do. The treatise discusses how opposite forces interact, and how unexpected new developments unfolding under the "fog of war" called for rapid decisions by alert commanders. In opposition to Antoine-Henri Jomini, he argued war could not be quantified or graphed or reduced to mapwork and graphs.

Perhaps most importantly, Clausewitz realized the correlation between politics and war. Clausewitz had many aphorisms, of which the most famous is, "War is not merely a political act, but also a political instrument, a continuation of political relations, a carrying out of the same by other means”. This view of warfare is still the standard viewpoint of war today.

What it is easy to overlook is that during his life and in the period when On War was first published, Clausewitz was regarded as a fairly insignificant figure, but in hindsight it’s easy to understand why his concepts have stood the test of time. While other military theorists focused on aspects of war that were applicable only to the tactics, equipment, and weapons of a particular period, Clausewitz looked instead at the philosophy which underpinned the strategy of warfare, something that remains unchanged by military technology or politics. Indeed, that approach has ensured Clausewitz remained relevant despite changes in tactics and technology. Soviet leader Vladimir Lenin studied Clausewitz and referred to him as “one of the great military writers”, and the strategy of deterrence pursued by the United States during the Cold War was inspired in part by President Dwight D. Eisenhower’s reading of Clausewitz’s book as a young officer in the Army in the 1920s. General George S. Patton was an avid reader of Clausewitz, as was Chinese Communist leader Mao Zedong, who organized a Clausewitz seminar for Communist Party members in the 1930s. The influential British military writer and thinker Basil Liddell Hart was clearly influenced by Clausewitz’s writings.

The list of those who were directly influenced or inspired by their reading of Clausewitz would cover many pages, so it’s all the more remarkable that On War was not completed at the time of his death in 1831. It was left to his widow, the Countess Marie von Brühl, to gather together writings that her husband had been working on for a number of years and pull these together into the book, which was first published in 1832. Nearly 190 years later, On War remains one of the most significant and brilliant expositions on political-military analysis and strategy ever produced, and it is also still one of the most influential books ever written on military (and non-military) strategic thinking.

Carl von Clausewitz: The Life and Legacy of the Prussian General Who Wrote On War looks at the life and career of the military officer and highlights the most important parts of his timeless work.