Understanding David Tudor's transition from performer to composer is critical to understanding his life and work. This task is made more complex, however, by the nature of Tudor's work as a performer. Because he specialized in the realization of indeterminate scores and entered into such close collaboration with avantgarde composers, the distinction between performer and composer is often unclear in Tudor's performances. The author discusses Tudor's realization of John Cage's Variations II as a case study in identifying the overlapping of performer and composer roles, both within this specific realization and within the context of Tudor's history. Because this realization has much more in common with Tudor's own compositions than with Cage's musical ideas, it can be considered more a composition by David Tudor than a composition by John Cage.