ODB, born Russell Jones, had complained of chest pains before collapsing outside his Manhattan studio and was dead by the time paramedics arrived. The cause of death was not immediately clear. Mr Jones had recently finished a prison sentence for drug possession and escaping a rehabilitation clinic but no drug paraphernalia was found at the scene. Today would have been his 36th birthday.
ODB, also known as Ol' Dirty Bastard, Dirt McGirt and Big Baby Jesus, co-founded the nine-member Wu-Tang Clan with cousins Gary Grice (aka GZA) and Robert Diggs (aka RZA) in 1992. Its debut album - Enter the Wu-Tang (36 Chambers) - in 1993, was considered to be a revolution in the world of hardcore rap.
Sony Music describes its release as "striking a strategic, genre-expanding blow for the hip-hop nation. Eternally elevating the urban art form, it justly propelled the Wu-Tang Clan to the apex of rap music."
Damon Dash, founder of Roc-a-Fella records, for whom ODB had been preparing a comeback album, said: "Russell inspired all of us with his spirit, wit and tremendous heart. The world has lost a great talent, but we mourn the loss of our friend."
On stage ODB's performance was unorthodox - alternately slurred, hyper and nonsensical - but in the studio he was productive, releasing hit singles such as Shimmy Shimmy Ya and Got Your Money and appearing on remixes with artists such as Mariah Carey.
In February 1998, he crashed the stage at the Grammy Awards and snatched the microphone from singer Shawn Colvin as she accepted an award. He was upset over losing the best rap album Grammy to Sean "P Diddy" Combs and complained that he had spent a lot of money on new clothes because he thought he was going to win.
He lived on the edge of the law and often within inches of his life. Wounded in shootings and arrested on a long list of charges, including threatening security officers, illegally possessing body armour, driving with a suspended licence, shoplifting and threatening a former girlfriend.
In 2000, after escaping a court-ordered stint in a California rehabilitation centre, authorities searched for him for a month. He was finally arrested in a McDonald's car park in Philadelphia. Three days earlier he had given a surprise fugitive performance in a New York city concert with Wu-Tang.
In 2001, he was sentenced to two to four years in prison for drug possession, plus two concurrent years for escaping from the clinic. He was released in 2003 and immediately signed with Roc-a-Fella.
He failed to turn up for a Wu-Tang reunion show in New Jersey last Friday.
His mother, Cherry Brown, said: "To the public he was known as Ol' Dirty Bastard, but to me he was known as Rusty. The kindest most generous soul on earth. Russell was more than a rapper, he was a loving father, brother, uncle, and most of all, son."