The definition of the drum kit – and consensus regarding its appropriate study – have changed dramatically over the course of the instrument’s history. This chapter is a rough guide to unpacking that history, and in doing so it treats the drum kit not as a fixed object, but a theoretical concept. What follows is a discussion of the drum kit in theory divided into three parts: (1) the invention and changing status of the instrument; (2) the trajectory of drum kit studies within the wider field of musical instrument scholarship; and (3) a discussion of the ‘drumscape’ as a theoretical tool. Building on Kevin Dawe’s concept of the ‘guitarscape’, the drumscape is a lens through which to consider how the drum kit has been written about, thought about and talked about; the power and agency of the drum kit in culture and society; and what kind of experience it is to play the drum kit (an experience involving both the mind and the body). Viewed through the lens of the drumscape, the seemingly simple term ‘drum kit’ can be understood from at least four different but related perspectives: the drum kit is a technology, an ideological object, a material object, and a social relationship.