Master P created a hip-hop empire without registering on any mainstream radar. For several years, he operated solely in the rap underground, eventually surfacing in the mid-'90s as a recording artist and producer who knew exactly what his audience wanted. And what they wanted was gangsta rap. With his independent label No Limit, Master P gave them gangsta rap at its most basic -- violent, vulgar lyrics, hard-edged beats, whiny synthesizers, and blunted bass. He wasn't a great rapper, nor was anyone on No Limit; occasionally, the No Limit rappers were even talentless and clumsy...