Call it soul, call it funk, call it hip-hop; the deep-down core of African–American popular music has been both a centre to which performers and audiences have continually returned, and a centrifuge which has sent its styles and attitudes outwards into the full spectrum of popular music around the world. The pressure – both inward and outward – has often been kept high by an American music industry slow to move beyond the apartheid-like structures of its marketing systems, which, though ostensibly abandoned in the days since the ‘race records’ era (the 1920s through the 1950s), continue to shadow the industry's practices. However much cross-over there has been between black and white audiences, the continual reiteration of racial and generic boundaries in radio formats, retailing and chart-making has again and again forced black artists and producers to navigate between a vernacular aesthetic (often invoked as ‘the street’) and what the rapper Guru calls ‘mass appeal’ – the watering down of style targeted at an supposedly ‘broader’ (read: white) audience. So it has been that, within black communities, there has been an ongoing need to name and claim a music whose strategic inward turns refused what was often seen as a ‘sell-out’ appeal to white listeners, a music that set up shop right in the neighbourhood, via black (later ‘urban contemporary’) radio, charts, and retailers, and in the untallied vernacular traffic in dubbed tapes, deejay mixes, and bootlegs.