John Watts de Peyster, Sr. (March 9, 1821 – May 4, 1907)[1] was an American author on the art of war, philanthropist, and the Adjutant General of New York.

[13] Already a brigadier general of the state militia at the onset of the Civil War, he met with what he perceived (and declared) to be prejudiced resistance from Abraham Lincoln when he attempted to raise regiments for the Union Army.

[15] In 1861, de Peyster traveled to Washington, D.C., to solicit a commission as a brigadier general of the Regular Army and offered to raise two regiments of artillery, which he felt best suited his expertise and physical condition.

[18][19] The career militia officer had always suffered from poor health, and turned down a commission as a colonel of cavalry offered to him by New York Senator Ira Harris in June 1863 on behalf of Generals Joseph Hooker and Alfred Pleasonton, who may have had an eye towards de Peyster's social connections.

[16][20] Other notable figures with limited field experience who were promoted to brigadier general by Pleasonton at that time were Elon J. Farnsworth, son of a Congressman, Wesley Merritt, and George Armstrong Custer.

The hero at Oak Ridge was John Buford ... he not only showed the rarest tenacity, but his personal capacity made his cavalry accomplish marvels, and rival infantry in their steadfastness ... Glorious John Buford!General de Peyster was known as the largest developer in the village of Tivoli, New York, where he resided at his family home.

[9] An authority on fire fighting, in 1895 de Peyster erected a huge state-of-the-art brick building for the local department.

[25] Some of his works including detailing Maj. Gen. Joseph Hooker's influences on the Army of the Potomac leading up to the battle, both positive and negative.

[26] His writing also spoke of the brilliant accomplishments of Maj. Gen. George H. Thomas and led to his modern consideration as one of the finest commanders of the war.

[30] Another philanthropic contribution included building the first library at Franklin & Marshall College, and donating one of the largest and most distinct rare book collections about European military history, the 1,890 volume Watts de Peyster: Napoleon Buonaparte.

John Watts de Peyster was also a Vice President of the American Numismatic Society, and the namesake of Post #71 of the New York G.A.R.

[33] He was the author of Life of Field Marshal Torstenson (1855), The Dutch at the North Pole (1857), Caurausius, the Dutch Augustus (1858), Life of Baron Cohorn (1860), The Decisive Conflicts of the Late Civil War, or Slaveholder's Rebellion (1867), Personal and Military History of General Philip Kearny (1869), The Life and Misfortunes and the Military Career of Brig.-Gen. Sir John Johnson (1882), and Gypsies: Some Curious Investigations, Collected, Translated, Or Reprinted from Various Sources (1887), and contributor to numerous other books, biographies, publications, and articles.