Ambrose Bierce served during the American Civil War as a member of the Union Army's 9th Indiana Infantry Division, later as a topographical engineer, and fought at the battle of Shiloh. "An Occurrence at Owl Creek Bridge" was one of several stories he wrote based on what he had witnessed during the war.
Ernest Hemingway served as a Red Cross ambulance driver in Italy during World War I. He used autobiographical elements from wartime experiences in his novel, "A Farewell to Arms."
Edward L. Beach, Jr. served in various positions as a Navy Submarine officer during World War II, and earned many medals and citations. Drawing on his own experiences, he wrote the novel "Run Silent, Run Deep" which was later adapted to the big screen in 1958.
Joseph Heller served in the 12th Air Force during World War II. He later wrote about the insanity of war in "Catch-22."
Norman Mailer was drafted by the U.S. Army and served in the South Pacific with the 112th Cavalry during World War II. He drew on his military experiences when writing "The Naked and the Dead."
Leon Uris joined the U.S. Marine Corps at age seventeen and served as a radioman in the South Pacific during World War II. He wrote "Battle Cry" as a result, but is probably best known for his novel "Exodus."
Kurt Vonnegut was a U.S. infantry soldier in World War II who was captured in Germany and held as a prisoner of war, with several other soldiers, in the underground meat locker of a slaughterhouse in Dresden. Because of their location, they survived when Dresden was bombed. His used his experiences as a POW, and the horrors he witnessed in the aftermath of the bombing, to provide material for his novel "Slaughterhouse Five," as well as several of his other books.
Richard Hooker (the pen name of H. Richard Hornberger) was a physician who served with the 8055th Mobile Army Surgical Hospital during the Korean War. In collaboration with W. C. Heinz, he wrote "M.A.S.H." and based one of the main characters, Hawkeye Pierce, on himself.
Ron Kovic served two tours of duty in Vietnam with the Marine Corps before being shot in combat. He sustained multiple injuries and was partially paralyzed. His book "Born on the Fourth of July" was made into a movie starring Tom Cruise as Kovic, and inspired Bruce Springsteen's song "Shut Out the Light" and Tom Paxton's song which was titled the same as Kovic's novel.
There are others, but these are representative of men who either became writers after their war experiences, or whose writing was influenced by them. They have shared their stories with us, and given their lives for us. The least we can do, on this Veterans Day, for them and all those who serve to protect our freedom, is to let them know we appreciate their sacrifices .
[Source for some of this information was: http://en.wikipedia.org/wiki/List_of_authors_in_war]