Jon Christopher Nelson’s Fantasies and Flourishes: An Interactive Concerto for Disklavier and Orchestra (1995) is the first interactive work to present the Disklavier as the solo instrument in a concerto with orchestra. The purpose of this study is to provide an analysis of Fantasies and Flourishes and advice on how to successfully present it in performance. Fantasies and Flourishes reveals the composer’s interest in the music of Elliot Carter, in particular his A Symphony of Three Orchestras. The entire work is based on the two all-interval tetrachords also used by Carter; in Fantasies and Flourishes, these tetrachords are combined to form seven octachords that are used in various manipulations. The Disklavier is an acoustic piano that can be played by a performer, can play by itself, or can be controlled by a computer program. In interactive works for Disklavier, a pianist plays on the Disklavier while the Disklavier plays by itself, much like if a pianist were to play on a player piano while the piano was also playing by itself. However, in interactive Disklavier music the pianist’s performance affects what the Disklavier plays; particular notes in the piano part trigger the Disklavier’s music. Chapter I provides an introduction to the dissertation and background on the composition. Chapter II gives a formal analysis of the work, with focus on the composer’s use of musical constraints to delineate form. Chapter III supplies information that will help a pianist to prepare for a performance of the concerto and includes discussion of extended techniques used in performance. Chapter IV gives a detailed discussion of Max, the computer program used to control the Disklavier. Analysis and description of the computer program give the performer insight into how the Disklavier’s music works, especially for algorithmically-composed sections that vary between performances. A chart is provided that details information regarding each trigger that the performer must play in order for the Disklavier to function properly.