This book seeks to shed light on Gurian musical aesthetics by identifying the unwritten rules followed by folk singers while improvising. To this end the variations of cadential phrases in twenty-four Gurian folk song transcriptions most of them trio songs are analyzed. There is also a fieldwork component: an on-site exploration of how five Tbilisi-based choirs resemble and differ in their musical approaches preferences and the modi operandi of their rehearsals.