If you want to be as brutal as a good battle rhyme, you could reduce the story of modern mainstream hip-hop to two rappers: LL Cool J and Jay-Z. There was plenty of great hip-hop before LL tossed his fat gold chain into the ring in 1985, but if Run-D.M.C. invented rap's "new school," with the raw beats and rough delivery that LL Cool J merely imitated, then LL was the first rap star who was raised on the music.
His success over the next 15 years -- a longer lifetime in the spotlight than any rapper has known -- was built on an emerging duality: LL's ability to affect different personas for different fans. Fighter and lover, conspicuous consumer and around-the-way homeboy, egocentric poseur and self-deprecating comedian (he invented the crazy-ass hip-hop loser Cheesy Rat a full decade before Eminem's Slim Shady), LL proves that mainstream players must eventually alienate the hood from which they come.
The one zone he wasn't willing to enter -- the hard thug world -- has now been taken up by Jay-Z, who stretches LL's duality to the schizophrenic breaking point. It's doubtful that LL will ever again manage anything as rough and smooth as Jay-Z's latest album, but if he does, you can bet he won't call it a comeback -- again.