This thesis begins by tracing the rise of the piano etude from Chopin to Ligeti, establishing historical and compositional precedence for Ligeti's Etudes pour piano. Special emphasis is given to the formal, virtuosic, and rhythmic development in the etude in the hands of selected composers, as these are the central features to be discussed in Ligeti's music. Formally, examples drawn from Debussy's etudes show experimentation in defining form using sonority and figuration. Technically, the etudes of Liszt and Rachmaninov set a new level of proficiency at the keyboard with their dazzling virtuosity. Excerpts showing polyrhythmic passages and the manipulation of rhythm are extracted from the etudes of Chopin, Skryabin, Bartok, Prokofiev and Stravinsky. These examples also show hemiola as a starting point for rhythmic and temporal complexity. A compositional and pianistic overview of Ligeti's three books of Etudes pour piano and a brief chapter on Ligeti's life and musical style follow. However, the core of this document is an in-depth analysis of Automne a Varsovie and a discussion of formal principles and the effect of "chaotic order" as achieved through the manipulation of rhythmic perception. The basic structural musical shape of Automne a Varsovie consists of an expectant build to climax followed by a sudden sabotage of musical momentum. This is achieved primarily through the accumulation and subsequent disintegration of texture, dynamic, and rhythmic complexity, as shown through numerous music examples. The effect of chaos is achieved through the manipulation of rhythmic perception---in particular, Western notions of such. Central African music and the player piano music of Nancarrow are discussed as non-traditional influences. Further, extensive illustration of the rhythmic illusion inherent in the hemiola and Ligeti's innovations in extending this principle are discussed. The last chapter of this document deals with the relationship between performance and traditional, "serious" analysis by questioning the usefulness of such detailed analysis of Automne a Varsovie in practical performance. Referencing writings by Cone, Meyer, Berry, Rink, and Fisk, the concluding chapter also describes some interpretative choices and other types of analysis used in preparing a meaningful performance of this work.