While Rock and Roll generally refers to an early (50s) brand of popular music, the general term Rock embraces a multitude of artists and styles. Even the standard instrumentation—guitar, bass, drums, vocalist—is far from universal across popular music’s seven-decade history. Nor, in the ‘post-rock’ world, can we rely on the safety belt of a 4:4 beat and verse-chorus-verse structure. You could build a city from the sub-genres of rock and populate it with artists of every kind and style. So perhaps all we can say is that your favourite artists may well be here. Unless they’re somewhere e...