As one third of the legendary New York rap group Run-DMC, Jam Master Jay was among hip-hop's true pioneers.

His hard, pounding beats and deft scratching formed the backbone of the trio's groundbreaking sound which helped to introduce hip-hop to the MTV audience.

And his instinctive production skills were instrumental in cementing the group's crossover status on 1980s hits like King of Rock and Walk This Way.

The 37-year-old DJ, born Jason Mizell in a comfortable middle class district of Queens, was 13 when he first went behind the turntables in public.

His group sold 3m copies of the album Raising Hell

"First parties I DJ-ed, there were no hip-hop records," he later recalled. "You created hip-hop from other records.

"We used to play in the park, hook the sound-system up to the street lamp, get the electricity that way. Hip-hop has always been about playing live - and working a crowd."

Rhyming

Mizell was brought into the group by childhood friends Joseph Simmons (Run) - brother of Def Jam co-founder Russell - and Darryl McDaniels (DMC) to provide the beats for their rapidly emerging rhyming skills.

In 1983 the group released their first single, It's Like That, on an independent label. It was well received by the local B-boys in Queens and became a national US hit.

At their height in the mid-1980s they were rap's biggest act

The video for their third single Rock Box, a hard rock-based rap with guitar riffs, broke the mould by getting on to MTV - a rarity for black artists of any genre during that era.

Their 1984 self-titled debut album became the first rap LP to go gold; the following year's King Of Rock went platinum; and 1986's Raising Hell became the biggest-selling album in rap history, moving more than 3m copies.

In their trademark unlaced Adidas trainers, fedora hats and black jeans, Run-DMC were - for a large part of the mid-1980s - the ubiquitous face of what would later come to be known as "old-school" hip-hop.

As the smiling DJ who preferred to let his colleagues do most of the the talking, Jam Master Jay was an integral part of the story.