This chapter introduces the concepts of “music” and “popular music”, and their main components. It systematises the various definitions of music, discuss the notion of universality in music, and particularly its social dimension. It defines and contextualises popular music, outlines the development of the main trends within academic research, and deepens the notions of melody, rhythm, harmony, lyrics, form and sound. Finally, the chapter describes the various figures/characters that are relevant in popular music analysis, from authors and performers to less obvious ones.