Sheet music for the collected works of Joplin were published in two volumes by the New York Public Library in the 1970's. Volume 1 was works for piano, and volume 2 works for voice, including the score for his only known opera, Treemonisha (1911). He wrote another one, called "A Guest of Honor" (~1903), but no copies are known to exist. Volume 1 was later released in softback by Belwyn Mills.