But the sound finally exploded with audiences when the group remade the Aerosmith (news - web sites) hit "Walk This Way," creating hip-hop's biggest crossover success of the time.

Many fans and artists cite the song as the first rap record they ever heard, and rap and rock groups alike continue trying to recapture the song's mix of raw hooks and big beats punctuated by half-shouted lyrics.

Though rap videos were rare on MTV at the time, "Walk This Way," with its elaborate story line of a comical grudge match between rappers and rockers, was a constant fixture on the station for months. The members of the group made an unforgettable impression with their black outfits and hats and white Adidas sneakers.

"Raising Hell," the 1986 record that included "Walk This Way," "My Adidas," and "It's Tricky," sold more than 3 million copies, becoming the first rap album to go multiplatinum. The group's self-titled debut album in 1984 was the first rap album to go gold.

Mizell wasn't the first to manipulate records by scratching them in time under a needle. But he did become one of hip-hop's best known and most respected DJs through his deft scratching and the group's spirited promotion of his skills.

A song called "Jam Master Jay" announced, "We got the master of a disco scratch/there's not a break that he can't catch. ... Behind the turntables is where he stands/Then there is the movement of his hands/So when asked who's the best, y'all should say/Run-DMC and Jam Master Jay."

The group's cheerfully competitive wordplay had always promoted education and clean-living, but members were nonetheless linked to gang violence when fighting broke out on several stops of their national tour in support of "Raising Hell."