Sun, YihanWhile my colleagues in collaborative piano graduate studies were focusing on learning violin and cello repertoire, I found an affinity for the burnished, dark sound of the viola. I became interested in how the instrument evolved from mainly a background middle voice throughout the eighteenth century, to being worthy of solo star status in the later part of the nineteenth into the twentieth century. In this dissertation, I plan on exploring twentieth-century virtuoso viola and piano literature written between 1907 and 1979. The repertoire includes both sonatas and suites by composers Dmitri Shostakovich, York Bowen, Rebecca Clarke, George Rochberg, Paul Hindemith, and Ernest Bloch. Analyzing how these composers navigate and expand the tonal and coloristic possibilities of the instrument will provide valuable insights for the interpretation of their works. From the collaborative pianist’s perspective, I aim to address key issues of balance and color when playing with lower-voice string instruments. Additionally, I will discuss the challenges involved in preparing and performing each individual piece and propose solutions to these challenges. This DMA collaborative piano performance dissertation project included one lecture recital, two collaborative recitals, and extended program notes. All three recitals were performed in the Gildenhorn Recital Hall at the University of Maryland, College Park, Maryland. All three recitals were performed in 2023: the first on February 11th, with violist William Satterfield, and the second and third with violist Yu-Hsuan Chen on March 7th and May 11th respectively. The live audio recordings of these three recitals can be found in the Digital Repository of the University of Maryland (DRUM).enDissertationMusic