This massive work composed by Jomini was the premier military strategy composition of the 19th century. Even the works of Clausewitz were not studied quite as much as this teacher of the Napoleon method of warfare. In fact it was Jomini (perhaps more than any other strategist) who influenced the leadership of both the Union and the Confederacy during the American Civil War. The Art of War is one of the first and most enduring textbooks on modern war.