In 1824, Schubert composed Octet in F Major, D.803, op. 166, for clarinet, bassoon, horn, 2 violins, viola, cello and double bass. The Octet comprises six movements and lasts approximately an hour. The work represents the pinnacle of the genre in the nineteenth century. The purpose of this dissertation is to provide important resources needed for a cohesive and informed interpretation of Schubert's Octet. The historical perspectives, which include discussion of Beethoven's influence and the genesis of the Octet, provide the context from which to discuss the Octet's musical language and performance practice. In turn, the analysis of its musical language informs the expressive opportunities as well as raises awareness to some performance considerations. The analysis focuses on Schubert's thematic and harmonic procedures, and explores the musical elements, such as the cyclic motif with which Schubert unites the piece. The dissertation also addresses revisions in the first publication, general editorial issues and discrepancies among the different editions. Finally, the dissertation concludes with an investigation of the performance practice through examination of recordings, and research into the nineteenth-century performance practice.