‘Rock’ is a term that is instantly evocative and frustratingly vague. Rock may mean rebellion in musical form, distorted guitars, aggressive drumming, and bad attitude. But rock has also stood for much more than a single style of musical performance. Very diverse sounds and stars, including country blues, early Bob Dylan, Motown, Otis Redding, Kraftwerk, P-Funk, salsa, Run-DMC, Garth Brooks and Squirrel Nut Zippers, have all been called ‘rock’ at one time or another, even though they are also equally describable as non-rock. If this eclectic set of performers and sounds can be grouped under the heading ‘rock’, it is not because of some shared, timeless, musical essence; rather, specific historical contexts, audiences, critical discourses, and industrial practices have worked to shape particular perceptions of this or that music or musician as belonging to ‘rock’. At the same time, no style or performer is automatically entitled to the ‘rock’ mantle, since rock culture has also been defined historically by its processes of exclusion. The idea of rock involves a rejection of those aspects of mass-distributed music which are believed to be soft, safe or trivial, those things which may be dismissed as worthless ‘pop’ – the very opposite of rock. Instead, the styles, genres and performers that are thought to merit the name ‘rock’ must be seen as serious, significant and legitimate in some way. These various conceptions of rock are made more complicated by the ways in which the meanings of ‘rock’ have shifted over the past four decades, and by how those meanings have been understood in different contexts or by different communities.