Mos Def started out as a Native Tongues affiliate, so A Tribe Called Quest's buoyant uplift and De La Soul's jaundiced wit are present in his own work. But his roots as an MC go even further back, to the sly storytelling of Slick Rick and the streetwise enlightenment of Boogie Down Productions. And pioneering black rockers Bad Brains and Living Colour spurred his own experiments with live bands.