This thesis investigates and critiques the taxonomical criteria associated with Franz Schubert’s piano music for four hands. The classification of piano duets as salon music, with a utilitarian, pedagogical, perfunctory, and entertaining function, has resulted in the majority of these works being sidelined from serious scholarly enquiry. Indeed, the complex aesthetic of the early nineteenth-century salon has yet to be fully probed in relation to Schubert’s transformation of the piano duet medium. This thesis aims to firstly, expose the disparaging discourses regarding salon music which have manifested in the reception history of Schubert’s piano duet music, and secondly, to investigate Schubert’s unique ambition in this area. Schubert’s earliest innovations are evident in his decision to merge a typically solo piano genre – the fantasia – with the four-hand medium. It is such early ambitions which propelled the investigation into theories of genre: How does a category become established? Can we differentiate between genre and medium? What effect has the (collective) categorisation of the piano duets had on the reception of these works? Such questioning critiques the classification methodologies of Carl Dahlhaus, whose approach is still apparent in the most recent musicological discourses regarding Schubert and genre. The revisionist work done on genre by Jim Samson and Jeffrey Kallberg has argued that understanding a generic group by mere classification ignores and dismisses the communicative aesthetic of genre; they also accentuate that early nineteenth-century genres are, by nature, flexible and not fixed. Whereas Samson and Kallberg have focussed their attention on the generic identity of Chopin’s solo piano music, a considerable lacuna exists in Schubert scholarship regarding the significance of theories of genre and their persuasive role in the reception of the composer’s four-hand repertoire. The latter part of the thesis focuses on one generic group – the fantasia – which Schubert explored via various mediums: solo piano, duet piano and one work for violin and piano. By adapting Kallberg’s paradigm of genre, the analytical section of this dissertation elucidates the role of medium, performer, audience, and form in Schubert’s four-hand fantasias. A comprehensive appraisal of Schubert’s formative influence in the cyclical sonata-fantasia of the early nineteenth century will be presented.