Suicide note set to music. Just him and his guitar. Returned to sender in his Answer To The Last Letter ('39), covered by Ray Price.
Ernest Tubb [on Just Call Me Lonesome, a Rex Griffin concept album]
Jack Greene [again a hit]
Bob Dylan [his To Ramona sounds as if it's influenced by The Last Letter; in fact it is an open letter, with lyrics reminding My Melancholy Baby (see there)]
Also by The Carter Family, Wilf Carter, Eddy Arnold, Hawkshaw Hawkins, Hank Snow, Jerry Lee Lewis, Marty Robbins, Wanda Jackson, Dottie West, Asleep At The Wheel, Waylon Jennings and Merle Haggard. To Ramona was covered by Alan Price, Sir Douglas Quintet, David Gray, Lee Hazlewood and Wilco Johnson.