The analytical literature posits a dichotomy between Copland’s “popular” and “serious” music. Despite different motivic and hannonic structures on the surface, however, these styles are consistent in their underlying use of tonality. Tonics in both styles are defined by the same set of tonicizing techniques; and tonics in both styles serve the same function — to define the changing scale-degree function of pcs that are emphasized in various ways as common to the collections of successive tonics. The most important of these changes in scale-degree function are summarized in pitch-class continuity graphs that show the relation of the changes to thematic and harmonic form. Detailed analyses, which cover two “popular” and two “serious” works by Copland, demonstrate the consistency between the two styles. Besides demonstrating an underlying stylistic consistency these graphs provide useful information about structure in Copland’s music because they confirm striking features of Copland’s thematic and tonal designs. / Arts, Faculty of / Music, School of / Graduate