Repulsive and compulsive, Mike Tyson touches nerves. And his story might just be the most fascinating study of the human condition across the past 30 years of sport.
For so long, he's been too drunk or too high - often both at the same time - to tell it.
At 47, he has reached an age many predicted he would never see. He looks well, still intimidating but also accommodating.
Before our interview, coinciding with the release of his autobiography, The Undisputed Truth, there is not so much as a second of awkwardness as he breaks into a soliloquy about rugby and how those who play it need certifying. This from a man who once munched on Evander Holyfield's ear.
It is sometimes tempting as an interviewer to play the role of psychiatrist, try to force a sporting personality to bare heart and soul. But only the most experienced medical professionals - and perhaps only a few of them - could begin to unpick the mind of Tyson.
Either side of a conviction for rape, he won and lost the world heavyweight championship and prompted legendary trainer Emanuel Steward to rank him as the most exciting heavyweight of the past half-century.
Having earned hundreds of millions of dollars, in recent years he remembers counting the items in his supermarket trolley for fear of being embarrassed at the checkout.
"I've either been dirt poor, almost homeless, or else I had all the money in the world," says Tyson. "I've never been balanced before. We're not rich but we're not broke."
Now married to Kiki, his third wife, he is forever sparring with temptation. "What date is it today?" he asks at one point. "On December 14th, I'll be four months clean.
"I'm not going to sit here and tell you I'm not going to drink again or get high," he adds. "Hopefully, I won't make a fool of myself. That's what normally happens, normally I won't stop till I'm arrested or I'm in a car accident.
"But you don't hear anything about me now. I don't go to clubs no more, I don't have 45 girlfriends."
In Las Vegas in November 1986, at the age of 20, Tyson became the youngest world heavyweight champion in history when a single left hook in the second round floored Trevor Berbick three times. Referee Mills Lane said every one of Tyson's punches "had goodnight written on it".
Missing from the celebrations was the man who had shaped the teenaged Tyson. Cus D'Amato, an irascible white trainer based in the Catskill Mountains in upstate New York, nurtured Tyson after they came together via the Tryon School for Boys, a young offenders institution, in 1979. D'Amato died a year before his protege's crowning glory.
"Cus had an extraordinary impact on my life," says Tyson. "He adopted me, pretty much became my legal guardian, like my father figure. I never knew what it was like for most people that had fathers.
"He'd call his old friends, 70 and 80 years old, and tell them: 'I've got this kid, he's only 14 and he's going to be the heavyweight champion of the world.' He would light up like a light bulb."
A birth certificate names Mike's father as Percell Tyson. They never met. The man Tyson came to know as his dad, Jimmy Kirkpatrick, was rarely on the scene in Brownsville, Brooklyn, a "drug-fested, crime-infested neighbourhood".
"I wouldn't go to school because people would pick on me," says Tyson. "I was really fat and had a lisp. I so desperately wanted to be like the so-called tough guys. I started flying pigeons with these guys and they had me help them build a pigeon coop.
"When I was just a little kid, 10 or 11 years old, they went to this school dance. I never knew you had to go home and change and wash. So I went to this little centre and they all started laughing at me because I had pigeon droppings on me, tar on me, I didn't wash. I smelled and I laughed at myself too.
"One of the older kids told me to meet him at the pigeon coop the next morning and he taught me how to rob houses and we spent the whole day robbing. He took me shopping, bought me a whole bunch of new clothes and told me to go to the school dance the next weekend. It was totally different.
"People didn't know I was the same guy they were laughing at last week. Psychologically, I knew then it was all about how you represented yourself."
His first reign as world champion was brought to a close in February 1990 in Tokyo, when he was knocked out in the 10th round by James 'Buster' Douglas in one of the most shocking upsets in boxing history. He slept with two women on the eve of the fight.
"I'd done it before against better fighters and was successful," he says, "so I thought I could do it again with a lesser fighter."
In 1992, he was convicted of raping a beauty pageant contestant in Indiana and served half of a six-year prison sentence. He claims, vehemently, that he was the victim of a miscarriage of justice and at this point the interview becomes uncomfortable.
When I remind him that women's rights campaigners protested about his visits to Britain to fight (twice) in 2000, he bristles. "What do they want from me? You tell me, seeing as you're asking the questions. You tell me."
He rejects my suggestion that he is asking for acceptance, having "done the crime and served the time". "Don't put words in my mouth," he says. "Do you hear me?"
While there were dissenters 13 years ago, others welcomed him with open arms. Brixton was reduced to a standstill and whipped into an orgy of adulation. To avoid the stampede, Tyson had to take refuge in, of all places, a police station. "He is a hero to people here," said a local community leader at the time, "whether we like it or not."
They had come to salute Tyson the boxer, whose place in sporting history was secure. Of all the great names to hold the heavyweight title, he got there quickest - at a younger age than Ali, Louis, Dempsey and the rest.
Tyson's second reign as world champion began with a pummelling of British hero Frank Bruno and ended with a one-sided defeat by Holyfield. Tyson regrets biting Holyfield's ear in their infamous rematch in 1997, although he insists he was butted 10 times without any intervention from the referee.
And that, many will claim, is Tyson's main flaw: nothing ever seems to be his fault and there always seems to be someone else to blame, whether in or out of the ring.
How much his violent upbringing has had to bear on his personality is impossible to calculate. Where many of us enjoyed love and affection, he knew only guns and knives.
He talks of having "paid for a lot of funerals" down the years, as friend after friend succumbed to the lawlessness of the concrete jungle.
Tragedy has been a regular visitor in his life. His voice dips as he recalls how, in 2009, his four-year-old daughter Exodus was killed in an accident involving a treadmill machine.
"I realised when I got to the hospital, everyone on the whole floor had lost their baby or was just about to lose them," he says. "Everybody came over to me to console me, because I was well-known.
"But I didn't deserve to be consoled. They lost their babies too. I realised then I didn't have exclusivity to pain."
The father of six other children, Tyson's ambitions now are to become a better parent and to stay clean.
"To everyone else, it's a normal life," he says. "To me, it's like being a monk in my little shrine. I have a lot to lose."
You can listen to the full interview with Mike Tyson by downloading the 5 live Sport podcast.