Dennis Hart Mahan
– September 16
) was a noted American military theorist
and professor at the United States Military Academy
at West Point
from 1824-1871. He was the father of American naval historian and theorist Rear Admiral Alfred Thayer Mahan
. Of his other four children, his son Frederick August Mahan also graduated from West Point in 1867.
A native of New York City
, Mahan graduated from West Point in 1824, first in his class. Such was his acumen that in his third year he was appointed acting assistant professor of mathematics. After graduation, he started teaching at the Military Academy with the very next class of cadets (1824). In 1826, he was sent to Europe
to study advanced engineering techniques and military institutions. Upon returning to West Point in 1830, he was promoted to Professor of Civil and Military Engineering. He resigned his commission in 1832 to accept the position of Chair of the Engineering Department.
As a teacher of military science at West Point, in addition to engineering methodology, Mahan promoted defensive tactics and strategy on the battlefield. His books on military engineering and defensive fortifications were widely influential. His writings became standard textbooks in the world-wide field from the time they were written until after World War I.
Professor Mahan's lectures and writings about military fortifications were instrumental in the conduct of the Civil War by the officers on both sides because most of the Civil War commanders, whether Union or Confederate, learned about entrenchment, fortifications, and how to conduct siege warfare from when they were cadets in the classes that he taught at West Point, and from his pre-Civil War writings. His influence was particularly felt during the Siege of Petersburg, where his theories affected the lives of the nearly 200,000 men in the trenches around both Petersburg and Richmond, Virginia.
Books by Dennis Hart Mahan
- Treatise on Field Fortifications (1836)
- Elementary Course of Civil Engineering (1837; revised 1868)
- Elementary Treatise on Advanced Guard, Outposts, and Detachment Service of Troops (1847; revised, 1862)
- Summary on the Cause of Permanent Fortifications and of the Attack and Defense of Permanent Works (1850)
- Elementary Treatise on Industrial Drawing (1853)
- Editor, with additions, the American edition of Mosely's Mechanical Principles of Engineering and Architecture (1856)
- Descriptive Geometry, as applied to the Drawing of Fortifications and Stereometry (1864)
- An Elementary Course on Military Engineering [covering] Field Fortifications, Military Mining, and Siege Operations (1865)
- Permanent Fortifications (1867)