Antoine-Henri Jomini (1779-1869) was a Swiss soldier and leading military theorist, whose classical ideas influenced all military strategists and military historians of the 19th and 20th century. His geometrical approach contrasted sharply with the equally influential ideas of his German contemporary, Carl von Clausewitz (1780-1831). who stressed the moral and political aspects of war.
Jomini was born in Switzerland, served in Napoleon's army from 1804 to 1813, and then joined the army of Tsar Alexander I. He helped to revolutionize warfare through his publications that appeared from 1807 to 1834.
Jomini used a classical, Newtonian model that saw history as a body of empirical data from which one could derive timeless principles. He stressed maps that showed the "forces" (a Newtonian concept) and stressed the importance of quantitative data. Jomini-style history emphasized maps, with every unit and its strength clearly marked, with arrows to show movement of forces. He argued the immutable geometrical principle that "to be superior to the enemy at the decisive point is the key to victory." Jomini emphasized information and the value of intelligence, based on his experience with good intelligence in the French armies. Jomini emphasized the offensive only insofar as it resulted in the capture of places—he believed the occupation of territory or strategic points more important than confronting the American army.
Influence in U.S.
Jomini was highly influential in America, where his disciples Dennis Mahan and Henry Wagner Halleck taught the great majority of top commanders on both sides of the U.S. Civil War. For example, As General-in-Chief of Lincoln's armies, Halleck was determined to apply the Jomini models to the Union armies in the East. This called for concentration, both strategically and tactically, with strong interior lines of communication between the two wings of the enemy. In his attempt to enforce these principles, Halleck met with little cooperation from General McClellan, who was slow to move his armies from the Potomac to support General Pope, and from the latter, who failed to observe Halleck's warning of an enemy attack from the rear. Faced with such obstruction, Halleck's plan failed and led to the defeat of Pope's armies by Robert E. Lee. Disciples of the Jomini-inspired "places theory" argued that the Confederacy could not stand without Vicksburg, New Orleans, Corinth, Atlanta, Chattanooga, and other key points, and made their capture the highest priority. 
- Jomini, Antoine Henri. The Art of War (1862) 410 pp, complete text online
- Jomini, Antoine Henri. Life of Napoleon translated by H. W. Halleck ; (1964) complete text vol 3 online
- Jomini, Antoine Henri. Jomini and His Summary of the Art of War: A Condensed Version (1965)
- Jomini, Antoine Henri (Baron de Jomini). The Political and Military History of the Campaign of Waterloo (1864) 227 pp. complete text online
- Stephen E. Ambrose, "Henry Halleck and the Second Bull Run Campaign." Civil War History 1960 6(3): 238-249. Issn: 0009-8078; Ambrose, Halleck: Lincoln's Chief of Staff (1996)