Tom Humphries/LockerRoom:In the past on television or in the cinema you knew the interior was an Irish interior if you saw Dev, JFK or the Sacred Heart (or in cases of acute piety, all three) sitting up on the wall. I imagine in the future the equivalent visual shorthand will be a copy of Roy Keane's autobiography leaning casually on a shelf.

The book is a pure, runaway, soaraway phenomenon. There are houses around the country where you would have been politely asked to leave if you brought a book in. Now the family gathers together to read the word of Keano. I know people who erected special little shelves to put the book on.

In time there will be university discussion groups examining the sacred text. Were those words the words that Keano would have used or were they the words of apostles. The devout will ask themselves in tricky ethical situations involving perceived lack of preparation: what Would Keano Do? Sadly and necessarily, the book finishes rather abruptly with Roy leaving Saipan. There is a two- or three-paragraph final round-up of beaten dockets and of frauds and chancers who are lined up against the wall and summarily shot and that's it. Closing credits.

Roy's fame and the coalition of his notoriety at the time and Eamon Dunphy's talent for gunslinging made the book what it is. I don't know how Roy feels about repeating the experience but I imagine there is a better book (if not quite so successful a book) in the chronicling of his life since Saipan. Things have changed in his life.

I don't know if Roy has read Richard Ford's classic The Sportswriter. The title is enough to put most people off. It's about life changing quickly like that and not very much about sport. There's a line in it about sport, though, that always resonates.

An old player notes that when you start seeing irony in sports you're dead.

Despite the headbanger image that the tabloids welded to him, Keane has always been able to stand back and laugh at himself. I interviewed him for the first time in 1994 when he was still more notorious off the pitch than on it .

I remember asking him about the risky combustibility of mixing nightclubs and pubs and fame and he smiled to himself and said that he'd been thinking the same thing himself the previous evening while sipping his cocoa and nibbling his chocolate biscuit.

"No really," he insisted and went on to wonder when a young fella with money could occupy some place in between the extremes. "Nine nights in a row you sit in on your own and eat chocolate biscuits and then one night you go out and it's trouble."

We came outside and he offered me a lift. He pointed me to a sober car in the corner of the car-park. I expressed disappointment that his famous red, sporty Merc with the ROY 1 reg wasn't on duty. He rolled his eyes. "What sort of a fool was I driving that thing around the place?"

I suspect that sometime down the road after that he worked it all out. Marriage, kids, changing his life in other ways. And football changed for him.

Appreciating the brevity of a career, he began funnelling himself totally into the game. Only those who run themselves into the dust day in and day out earn the right to shout and control other players the way Keane did for the last seven or eight years. He was never a lag. Never a chancer. Never short-changed the punter. No need to tell you. You knew him.

This past year has been tumultuous. You looked at Roy Keane's face on Wednesday night when he went to sit in the stand and the old desperado gauntness was gone from it. His eyes don't look haunted and his cheeks don't look scalloped out. The official explanation, and probably one that Roy genuinely believes, is that his hips have injuncted him from ever being the pre-Saipan Roy Keane again. He is in the process of reinventing himself, of finding a new use for his talents.

In the process, he has decommissioned his snarl and given up his right to bite other players. He wears his just takin' care of business face now on match days. Other things have changed. The charity stuff, which he always did with a ferocious sense of privacy, now sometimes includes a photo opportunity. He takes more press conferences. I imagine little old ladies are sick of him helping them across the road.

He looks like a man who has run his fingers along the seam of irony that marks his life. A guy who has looked at the demonised version of himself we've all seen and wondered what it's all about.

Roy's next book doesn't have to be filled out with more phoneys, frauds and conmen than an Elmore Leonard novel. It might start in his head in the hotel room in Saipan when he heard his team-mates moving on for Saipan.

Forget all the rights and wrongs and bitter stirrings. Since then Keane has been hung again for a tackle he committed long ago. He has seen his villainy explode almost unaccountably to comic-book proportions. He's seen Jason McAteer review his book in public, seen the plc he works for sell him down the river on the matter of his international retirement. He's seen his nemesis Mick McCarthy lose the Irish job and then become the losingest messiah in Premiership history, All that and the usual madness of a Premiership season. Ferguson's rages. Beckham's flashbulb life. The daily round of rumours and whispers. Who could blame Roy's body and mind for dissenting? If he asks his brain to tell his hips and his legs to grind themselves into full service one more time maybe his brain sends back a memo asking why.

On Wednesday at Old Trafford we had the litmus test on Roy Keane. More than any game this season, Real Madrid in the Champions League was one in which Keane yearned to dominate. It's the competition that haunts him and the company he belongs in. The dropping of Beckham, whom Roberto Carlos has twice killed for sport, was just a sideshow for the red-tops - the real drama was in Keane's struggle with himself.

In the end he was fine but nothing special. A ghost of himself, tidy and thoughtful and contained. The question is whether he can stand to be that. It's a hard thing to rage like a furnace when you aren't giving out the old heat. There was no irony in being a demonic obsessive who could swing games and win league titles and vanquish Juventus single-handedly. A hint of decrepitude though and the old rage and passion just heighten the pathos you carry with you.

Keane has too many enemies and too much pride to make an exhibition out of his waning. He could be a defender perhaps but you don't fancy the managing director, the boss of bosses, doing filing just to keep his hand in.

This last week will have amused him in a grim way. It saw United play their part in a piece of theatre that will have meant nothing to Keane and then meticulous Arsenal leave a two-goal lead behind in Bolton, handing Keane another league medal, which means virtually nothing to him.

And the hoi polloi wonder if David Beckham, who isn't good enough to play against Real Madrid, will be signed by Real Madrid because of his merchandising possibilities.

Maybe soon would be a good time to ask them to stop the carousel. Roy wants to get off.