In the study of popular music, much attention is given to the cover version, a performance of a song filled with reference to and even commentary upon previous performances. Analysis of cover versions tends to reveal a lot about the performers and performances but very little about the work being performed. Because different versions of a song may vary widely, it is often difficult to determine what precisely is ‘the work’ in the first place, especially in the absence of a score. Using an original analytical apparatus, the pitch-prevalence contour, and using Jimmy Webb's ‘Didn't We’ as a case study, this essay attempts to quantify the ‘core components’ of a song, the parts of a song that are retained in most if not all of its versions. It is through the analysis of various performances, seeking similarities, that one is able to see the essence of the song revealed. What is more, isolating these components simultaneously brings the differences in the performances into greater relief. The methodology thus separates the singer and the song.