Contemporary jazz musicians draw from a rich and varied collection of techniques and strategies used towards the realization of harmonic succession, voicing and voice-leading, and linear improvisation. While musicians recognize the distinctiveness of various jazz chord-scales and harmonies, they also talk about “source scales” and chord families, and describe processes that apply to the manipulation of chord progressions including chord and chord-scale substitution, interpolation, and reduction. Aligned to jazz theoretic discourse, this paper presents a model of set-class space in which scales and chords typical of the jazz language coalesce into pc-set genera and form inter-generic relations through transformation. The model suggests a holistic, theoretical definition of jazz harmony and offers musicians a way of thinking about relations among scales and harmonies in terms of a transformational system that resides in transformational space, which in turn can be employed systematically and imaginatively towards the creation and interpretation of jazz music.