Duende has long been a fixture of the gitano lifescape in Andalusia, Spain, and is often invoked in relation to flamenco performance with such variance in meaning that it is difficult to attain an understanding of what duende really is, and more importantly, what it means to contemporary flamenco performers. The word is often portrayed in spiritual and poetic terms, which are evocative but imprecise in definition. This thesis seeks to construct an understanding of duende that is derived from both the traditional gitano setting and the modern context of commercial performance, one that explains the phenomenon through the lenses of ethnomusicological theories of embodiment, the psychology of optimal experience (flow), and the neuroscience of musical experience. As a by-product of coming to an understanding of duende , I have constructed a theory of deep playing, which intersects with these phenomena. Deep playing privileges the experience of the performer, and describes a processual phenomenon with specific conditions and variables, with the key indicators expressed by Autonomic Nervous System arousal, and the climax demonstrated through a flood of chemical neurotransmitters, creating a feeling of transcendence.