Ethan Allen Hitchcock (May 18, 1798 – August 5, 1870) was a career U.S. Army officer and author who had War Department assignments in Washington, D.C., during the American Civil War, in which he served as a major general.

Hitchcock was born in Vergennes, Vermont, grandson of American Revolutionary War hero General Ethan Allen. He graduated from the United States Military Academy in 1817 and was commissioned a third lieutenant in the U.S. Artillery. From 1829 to 1833, he served as commandant of cadets at West Point and achieved the rank of the lieutenant colonel in the 3rd U.S. Infantry by 1842. He served in the Seminole War in Florida, in the Pacific Northwest, and in the Mexican-American War, where he served as Gen. Winfield Scott's inspector general in the march on Mexico City. He received a brevet promotion to colonel for Contreras and Churubusco and to brigadier general for Molino del Rey. In 1851 became the colonel of the 2nd U.S. Infantry. He resigned from the Army in 1855 following a refusal by Secretary of War Jefferson Davis to extend a four-month leave of absence that he had requested for reasons of health. He moved to St. Louis, Missouri, and a presumed retirement, occupying himself with writing and studies of general literature and philosophy.

After the start of the Civil War, Hitchcock applied to return to the service, but was rejected. It was only after the intervention of his former general, Winfield Scott, that he was commissioned a major general in the U.S. Army and became special adviser to the Secretary of War from February 17, 1862. From March 17 to July 23, 1862, he served as the chairman of the War Board, the organization that assisted President Abraham Lincoln and Secretary of War Edwin M. Stanton in the management of the War Department and the command of the Union armies during the period in which there was no general-in-chief. (Maj. Gen. George B. McClellan had been relieved of his responsibilities as general-in-chief and Maj. Gen. Henry W. Halleck had not yet replaced him.) From November 1862 through the end of the war, he served as Commissioner for Prisoner of War Exchange, and then Commissary-General of Prisoners until 1867. He was mustered out of the volunteer service in 1867 and moved to Charleston, South Carolina, then to Sparta, Georgia.

Hitchcock died in Sparta, and is buried in West Point National Cemetery, New York.

Known as the "Pen of the Army," Ethan Allen Hitchcock was recognized by his contemporaries as an avid reader of philosophy and a published scholar. Today he is credited as an early influence on the development of Jungian psychology.

By the time of his death, Hitchcock had amassed a large private library of philosophical texts, including over 250 volumes on the subject of alchemy. This collection was widely regarded as one of the finest private holdings of rare alchemical works and is preserved by St. Louis Mercantile Library at the University of Missouri-St. Louis. These books informed Hitchcock’s writings on the subject of the psychological content of alchemy, which in turned influenced the 20th century studies of Swiss psychiatrist Carl Jung. Through Remarks upon Alchemy and the Alchemists and other writings, Hitchcock argued that the alchemists were actually religious philosophers writing in symbolism. In Problems of Mysticism and its Symbolism, the Viennese psychologist Herbert Silberer credited Hitchcock with helping to open the way for his explorations of the psychological content of alchemy. In turn, Jung acknowledged Silberer's work on alchemy in his own major study, Psychology and Alchemy.

* Remarks upon Alchemy and Alchemists (published in 1857) * Christ the Spirit (1861) * The Story of the Red Book of Appin (1863) * Spenser's Poem (1865) * Remarks on the Sonnets of Shakespeare (1867) * Fifty Years in Camp and Field (posthumous, 1909) * A Traveler in Indian Territory: The Journal of Ethan Allen Hitchcock, Late Major-General in the United States Army (posthumous, 1930)

* Eicher, John H., and Eicher, David J., Civil War High Commands, Stanford University Press, 2001, ISBN 0-8047-3641-3. * Warner, Ezra J., Generals in Blue: Lives of the Union Commanders, Louisiana State University Press, 1964, ISBN 0-8071-0822-7. *Military biography of Ethan Allen Hitchcock at Corpus Christi public library