This analytical study of Elliott Carter's Piano Sonata focuses on middleground structural aspects found in the work such as phrases, phrase groupings, cadences and note collections. These are examined under four main headings: The Articulation of Phrases looks at the division of large passages into phrases, showing the various ways in which new phrases are marked. These include sudden changes in texture and register, restatements of thematic material, and recurring characteristics that appear at important cadential points. The Unification of Extended Passages by Middleground Stepwise Motion focuses on the rising linear motion that connects the individual phrases of many of these larger passages. Correlations between thematic material and phrase contours are also explored. The Relationship of Vertical Intervals and Note Collections to the Character and Phrase Rhythm of Particular Passages further examines phrase articulation by means of changes in note collections, with distinctions among phrases arising from the correlation of consonant vertical intervals with passages of linear motion and dissonant vertical intervals with passages that are more static. Anticipation and Overlapping of Materials describes an important aspect of the Sonata's overall structure in which themes and motives, as well as characteristic intervals of these materials are used to link the two movements of the work by a network of anticipations and flashbacks. An examination of the final climactic Maestoso section of the first movement (mm. 252-264) provides a summary of the various compositional aspects described in this study. / Arts, Faculty of / Music, School of / Graduate