This is a stylistic study of the four versions of Liszt's Three Petrarchan Sonnets with special emphasis on the revision of poetic settings to the music. The various revisions over four versions from 1838 to 1861 reflect Liszt's artistic development as seen especially in his use of melody, harmony, tonality, color, tone painting, atmosphere, and form. His use of the voice and development of piano technique also play an important part in these sonnets. The sonnets were inexplicably linked with the fateful events in his life and were in a way an image of this most flamboyant and controversial personality. This study suggests Liszt's importance as an innovator, and his influence on later trends should not be underestimated.