John Caldwell Colt (March 1, 1810 – November 18, 1842), the brother of Samuel Colt of Colt firearm fame, was an American fur trader, bookkeeper, law clerk, and convicted murderer. He served briefly as a U.S. Marine, forging a letter to get himself discharged after three months. After numerous business ventures, he became an authority concerning double-entry bookkeeping and published a textbook concerning the subject, which had 45 editions and remained in continuous publication until 13 years after his death.