This thesis discusses the lieder of Richard Strauss including a comparison between Richard Strauss and Johannes Brahms.

The songs of Hugo Wolf represent the culmination of the Romantic German Lied tradition. Wolf developed a personal chromatic harmonic style that allowed him to respond to every nuance of a poetic text, thereby stretching tonality to its limits. He was convinced, however, that despite its novel nature his music could be explained through the traditional theory of harmony. This study determines the degree to which Wolf's belief is true, and begins with an evaluation of the current state of research into Wolf's harmonic practice. An explanation of my analytical method and its underlying philosophy follows; historical perspective is provided by tracing the development of three major elements of traditional theory from their inception to the present day: fundamental bass, fundamental chords, and tonal function. The analytical method is then applied to the works of Wolf's predecessors in order to allow comparison with Wolf. In the investigation of Wolf's harmonic practice the individual elements of traditional functional tonality are examined, focusing on Wolf's use of traditional harmonic functions in both traditional and innovative ways. This is followed by an investigation of the manner in which Wolf assembles these traditional elements into larger harmonic units. Tonal instability, rapid key shifts, progressive tonality, tonal ambiguity, and transient keys are hallmarks of his style. He frequently alters the quality of chords while retaining the function of their scale-degree root. Such "color" chords are classified, and their effect on harmonic progression examined. Wolf's repetitive motivic style and the devices that he employs to provide motion in his music are also discussed. I conclude by examining Wolf's most adventuresome techniques—including parallel chords successions, chromatic harmonic and melodic sequences, and successions of augmented triads--and the suspension of tonality that they produce. This project encompasses all of Wolf's songs, and should be a useful tool for Wolf scholars and performers, students of late nineteenth-century music, the music theorist, and for anyone interested in the concept of harmony as a stylistic determinant.