This chapter explores the establishment of the ‘Frantic Four’ era Status Quo and their final Long Play record for the Pye label, Dog of Two Head. Central to the compositional style of that album is the band’s continued development of blues-rock and 12-bar devices, as found in the tracks ‘Railroad’ and ‘Mean Girl’, combined with an espousal of the modal system for key melodic and harmonic elements. In respect of the latter, they draw on the Aeolian, Dorian, Mixolydian and Locrian modes for the composition of various styles. Examples include ‘Umleitung’, ‘Someone’s Learning’ and ‘Gerdundula’. In each case, the compositions creatively retain a sense of the archaic and arcane context of those modes to impart a serious tone and the impression of progressiverock. The essence of progressiverock is also evident in the band’s continued espousal and development of complex and lengthy structures—forms that have certain parallels in art music. Furthermore, the unique twin-guitar work of Rossi and Parfitt begins to make a substantial impact for the first time. This chapter also contains original interviews with Alan Lancaster.