American composer Roy Harris began writing a symphony for the Tommy Dorsey band in 1938, but the piece was never completed. This dissertation project chronicles the events surrounding the interesting collaboration between the composer and the bandleader, including problems incurred during the rehearsal process, the eventual abandonment of the project, and the discovery of the little-known band work. The paper includes information on the composer's life and works, an in-depth discussion of the compositional technique that Harris called “autogenesis,” and a detailed analysis of the two surviving movements of the band piece. The piece is also discussed comparatively with other significant works in Harris' symphonic genre, most notably his Folksong Symphony, also known as his Fourth Symphony. A significant portion of the research and preparation for the project was spent reconstructing a modern wind ensemble edition of the two surviving movements. A complete score of the reconstructed edition is included as part of this project.