This dissertation explores the themes of collaboration and creativity in the relationship between arranger Nelson Riddle and vocalists Frank Sinatra and Ella Fitzgerald. It examines the balance between structure and freedom as well as the specific musical results that emerge from collaboration between an arranger and vocalists who are considered among the greatest in their fields. An examination of their interactions, musical scores, and performances, reveals that the constraints that are present in a collaborative effort can lead the artists to find a shared process to make a creative, unified product.

This study examines the evolution of Ella Fitzgerald's scat syllable vocabulary during a key developmental period in her career when she was recording for Decca Records. Between 1943 and 1952, Fitzgerald established the syllabic vocabulary that would serve as a defining characteristic of her improvisational style for the rest of her career. Fitzgerald is commonly praised as the greatest vocal improviser in jazz history, but while much has been written about Fitzgerald's melodic and harmonic approach to jazz improvisation, little has been written about her syllabic approach. Timbre and articulation are considered to be vital elements of any jazz musician's style; the study examines the changes in Ella Fitzgerald's syllabic approach through transcription and analyses of thirteen scat solos recorded during this time period, using scat syllable choices to discuss timbre and articulation. This analysis provides a model for further research of its kind, as well as informing historically accurate performance practice by both teachers and students of jazz singing.