This monograph explores the integration of improvisation and orchestral music. It consists of two closely related large-scale compositions, Amphion and Zethos, and an accompanying essay. Amphion, for orchestra, is in three movements and includes frequent references to styles and genres of the Baroque era, specifically the French dance suite. Zethos, for five improvisers and chamber orchestra, includes the three movements of Amphion, in toto, plus five additional concertato sections with improvisation. These sections have multiple player configurations and were composed for specific players with distinct improvisational skills. These sections also fulfill specific functions in relation to the three fully notated movements of Amphion: as introductions, codas, transitions, and development.

The accompanying essay considers issues relevant to Amphion's and Zethos's rehearsal and performance, and examines their form and melodic/harmonic language. It also discusses the historical precedent and aesthetic rationale for improvisation in orchestral music, and the notation of improvisation in Zethos.