By comparing current solo “improvisations” ( taksim-s), recordings of such performances from the earlier part of the period studied (1910-2010), and the official classical Turkish music theory as formulated in textbooks of the twentieth century, this study firstly determines the differences between what performers do and what theorists say that performers do in regard to defining the Turkish makam (melodic mode) system. This information, gathered during forty-two weeks of Fulbright-Hays sponsored field research in Istanbul, Turkey in 2008 and 2009, is then used to elucidate an independent, previously unwritten “performers' theory” for Turkish makam music. The “principles of melodic movement (and modulation)” so derived are distinct from that aspect of makam theory that is characterized by makam definition per se (a subject that is the focus of virtually all twentieth-century Turkish makam theory texts). Two levels of such “principles” are discerned: the first—"principles of cins conjunction"—charts out every makam-evoking conjunction from all the possible combinations of trichords, tetrachords and pentachords (“cins-es”) recognized in the performers' theory and arranges the results in a “cins constellation” for each individual cins, showing each makam that may be evoked by moving from that cins up or down into any of its allowable neighbor cins-es. The second level of “principle”—“principles of motivity”—concern the means by which melodies are moved forward (whether or not in the context of modulation). They consist of: a pivot between two makam-iterations that share one cins at the same level; a shift in emphasis within a makam's tonal structure showing a new makam “existing inside” another makam; a direct change of cins at the same level; and, chromaticism in makam-s with diatonic tonal structures. As a whole these “principles of melodic movement” formalize a performer-oriented perspective upon Turkish makam music analogous to the theory of “functional harmony” in Western art music; they present a radically different way of understanding makam music than both traditional and current theoretical models, and yet work in parallel to these, altering without making them obsolete.