After leaving the United States Army, Truscott began work on his book "Command Missions", which was published in 1954 (), and "The Twilight of the U.S. Cavalry" (). The latter book was published after his death by his son, Lucian III, in 1989. In 1954, Congress passed Public Law 83-508, which promoted several World War II senior officers who had exercised responsibilities greater than their rank; as a numbered army commander, Truscott carried out the duties of a four-star general, and the 1954 law promoted him to general on the retired list.