Since the middle of the 19th century, Americans purchased pianos in increasing numbers. Families and friends gathered around the piano for evenings of musical fun. Piano players needed sheet music to learn the latest songs and publishers quickly printed everyone's favorite pieces, first in black and white and later with detailed chromolithographed color covers. The advent of radio and even television simply increased public awareness of hit songs, and the production of sheet music still grew. Eventually, use of sheet music lessened along with the popularity of home pianos in the middle and later 20th century. Radio, phonographs, and personal listening devices began to replace the piano in the parlor. Written in 1944, "I'll Walk Alone" follows the trend of many other World War II-era songs in detailing a relationship between a soldier and the woman he had to leave behind. This song tells the story of a woman who promises to remain faithful until her lover returns home from the war.