Even now, 20 years after he arrived at Manchester United, dressed in a blazer and an attitude that explained all over again the reason for Hadrian's Wall, the theory of some is that Sir Alex Ferguson has yet to provide a truly defining image of himself, a flash of revelation to carry us beyond all the anger and the joy, the obsession and the stored-up vengeance. They hold that the mystery of his competitive will is hidden somewhere between a still boyish love of battle and the angst of the ageing general who looks into the skull's head of his past and wonders if he will ever see another great victory.
The theorists are wrong, however, and anyone who was in the Nou Camp for the European Cup final of 1999, when his team became the running embodiment of his belief that defeat is not so much a thief in the night as an outrageous impostor, can say so with a special edge of conviction.
When Ferguson's eyes swivelled from the gut-wrenching sight of the colours of Bayern Munich being pinned to the trophy which had become his version of the Holy Grail to that of Ole Gunnar Solskjaer conjuring a winning goal something happened to him, at the age of 57, that you see in young boys when they leap ecstatically into the arms of their fathers.
What happened was the wonderment that comes only to those who still harbour in their gnarled old lives, and souls, a little corner of innocence. Seven years on, the force of that moment, its need to be reproduced, remains the magnet drawing out a career that is reaching beyond all precedent.
Innocence in the man who at times has seemed to wish for nothing more than the imposition of a rule of terror on all of English football? A man for whom loyalty has never been fashioned by sentiment but need - ask Roy Keane, ask Gordon Strachan, ask Jaap Stam, and, supremely, a David Beckham who thought he had reached the stage when he could operate at Old Trafford on his own terms? A man who could cry conspiracy at the mere run of the ball? A man who once confessed to not feeling an ounce of compassion when a sworn enemy was diagnosed with cancer because to do so would compromise his idea of his own honesty?A man for whom ferocious partisanship has been not a tendency but a deeply ingrained way of life?
Yes, it is the innocence that all of the great football men have always had and expressed in their belief that they could find an answer to a football problem, that potential would again flower gloriously - all wrapped in a passion that will not die and which one recent night persuaded Ferguson, just a few months short of his 65th birthday - an age at which the men he admired so much in his youth, Jock Stein, Bill Shankly and Sir Matt Busby, had long withdrawn from the front line of the battle - to go to the touchline in the rain and wind of a tricky night at Crewe.
When the moment of glory was ebbing in the Nou Camp, when the sight of him dancing down the touchline with his eyes glistening and his arms outstretched was already frozen in the memory of all who saw it, Ferguson was still stunned. He sat shaking his head and murmuring, "I can't believe it. I can't believe it." And then, a small phrase that radiated from the core of his existence, "Football - bloody hell." If they called Busby, who would have been 90 on the day Ferguson delivered United's second European Cup 31 years after the first, the father of United - and maybe even all of football - how could they describe the man who had picked up his tradition and given it a new and amazingly consistent dimension?
You couldn't call Fergie the father of anything except his burning desire to push back the barriers of his own ambition. He cleared out talented players like Norman Whiteside and Paul McGrath not because he didn't recognise their ability but because he questioned too deeply their will. They might have been money lenders in the temple.
He made mistakes, some of his signings were indifferent at best, but always there were moves that were as bold as they were inspired: Keane and Cantona were not exactly model citizens, but they were the catalysts of change that required the hardest of nerve; when the generation of Scholes, Giggs, Beckham and the Neville boys replaced a winning team, Alan Hansen, drawing on his Liverpool experience, announced that you couldn't win with kids. But you could, as Busby had proved 40 years earlier, if they were the right ones.
When Ferguson made a rare and fundamental mistake in the organisation of his life and his career, and prematurely announced his retirement, it was his wife and sons who saw most clearly that for him an honoured retirement would not be a prize but a sentence.
They wanted the vintage wine-drinking, horse-fancying maker of football empires to stay on the front line because they knew any alternative would be a shell of the man whose intensity - and furies - had shaped their lives. They knew that in the case of Sir Alexander Chapman Ferguson there was an unswerving obligation ... you took the best of the zealot and you lived, however turbulent the ride, with the rest.
The conventional path would have been to walk away, as some part of him said, with the glory piled so high: 17 major titles for United, including the unprecedented treble of Premiership, FA Cup and European Cup, and nine for Aberdeen.
But walk away to what? To a sudden hush. Better, he decided, to hear the boos that greeted him, for the first time, when United lost to Blackburn at Old Trafford a few years ago; better still to be cut and to bleed than to have everything settling into place, never again to be disturbed by the irreplaceable surges that come when you are on the line between winning and losing.
We do not yet know the outcome of his decision to walk back - whether it will be seen ultimately as an act of folly, an old man's wish to reinvent himself and the most thrilling days of his life - or a sensationally vindicated belief that there is still more than a little good wine left in the glass.
There is, however, an interim verdict to be delivered. It is that if Ferguson has yet to return to the mountain top of English or European football, he has already achieved something that seemed to be beyond anyone's power with the arrival of Roman Abramovich and Jose Mourinho at Chelsea.
He has brought a degree of suspense, and one that was brilliantly augmented last weekend when Bolton Wanderers, the anti-football specialists who pride themselves on delivering hammer blows to such aristocrats as United and Arsenal with football as spontaneous as an old May Day march past in Moscow, were played off their own park. Wayne Rooney, who some saw as the old gambler's last throw, re-emerged with a thunderous hat-trick. It meant Ferguson, with his arch-rival Arsène Wenger, could still be seen as an investor in a game that was about more than unabashed cynicism and spite.
Here, in the manner of United's open-hearted and flowing play, was another large hint of the innocence - and the courage behind a face that for some has long been seen as ruthlessly self-serving; a willingness to believe that the great prizes can still be won in a certain, thrilling way, and that he might still be the author of success which made no compromises with the meaning of football.
Sir Bobby Charlton saw it clearly enough when, as a United director, he elected himself to the job of finding a man who would not be dwarfed by the weight of Busby's legacy, a task that had been beyond such formidable football men as Frank O'Farrell, Tommy Docherty, Dave Sexton and Ron Atkinson.
"I saw what Alex had done with Aberdeen, " says Charlton. " I saw somebody who had the nerve and the belief to go out and get what he wanted; somebody who would never be overawed by any situation. Somebody who would give the job everything that was required - and someone who also saw it as the biggest challenge in football. I have never doubted any of this since the day of his appointment, and my confidence was not harmed by the fact that I saw the old man [Busby] felt the same way."
Such faith has, of course, been tested. Ferguson's war with the Irish horsemen plutocrats John Magnier and J P McManus was always going to be perilous in the shadow of the Glazer takeover. But Ferguson's imperatives in the matter of Rock Of Gibraltar, the horse he believed he partly owned, were similar to those in so much of the rest of his life. They were dictated by the values of his native Govan, where the tough shipbuilders and stevedores taught him that no time was too soon to fight for your rights.
Ferguson swears that he learnt more in Govan than in any of his football assignments. From his first games with Queen's Park and his hard-won success and subsequent angst with Rangers, his managerial survival ordeals with East Stirlingshire and St Mirren, and then his glory at Aberdeen and at Old Trafford, he carried the tough wharfside with him.
It proved a dimension that was probably best expressed in the wake of a 5-1 defeat by Manchester City, devastation that came when Old Trafford had still did not decided whether Ferguson was a messiah or just another lamb at the altar of a squandered dream. Ferguson felt he had let down every United supporter. He felt like a criminal, a betrayer.
This was a bleakness which still comes to him with every defeat. But then when United win, and when he is redeemed, there is the overwhelming desire to run like a boy. In the often jaded world of big-time football no one has done it for so long and with such competitive courage. For so many talented football men one bad season can feel like a lifetime.
The measure of Sir Alex Ferguson, still, is that so often he makes 20 years, with all the good and some of the bad, seem like a single heartbeat.
The trophy cabinet Fergie's triumphs
* PREMIERSHIP: 8
1992-93, 1993-94, 1995-96, 1996-97, 1998-99, 1999-00, 2000-01, 2002-03
* FA CUP: 5
1989-90, 1993-94, 1995-96, 1998-99, 2003-04
* LEAGUE AND CUP DOUBLE: 3
1993-94, 1995-96, 1998-99
* LEAGUE CUP: 2
A CHARITY/COMMUNITY SHIELD: 5
1993-94, 1994-95, 1996-97, 1997-98, 2003-04 (1990 Charity Shield was shared with Liverpool after drawn match)
* EUROPEAN CUP: 1
* THE TREBLE (Premiership, FA Cup and European Cup): 1
* EUROPEAN CUP-WINNERS' CUP: 1
* INTERCONTINENTAL CUP (Champions of Europe v Champions of South America): 1
* UEFA SUPER CUP (European Cup winners v Cup-Winners' Cup winners): 1
Football's history men The game's longest-serving managers
* GUY ROUX
AJ Auxerre (1961-2005) 44 years in charge
Ligue 2 Championship 1979-80
Ligue 1 Championship 1995-96
Coupe de France 1994, 1996, 2003, 2005
Copa Delle Alpi 1985, 1987
(Tournament first organised by Italian National League in 1960. It ran until 1987. Auxerre won when the competition was between French and Swiss teams - 1972-1987).
* JOSEPH 'SEPP' HERBERGER
Germany/West Germany (1936-63) 27 years in charge
World Cup 1954 World Cup (beat Hungary 3-2 in the final). In the meeting between the sides in the earlier rounds he rested the first team because he thought they would lose anyway.
* MATT BUSBY
(1945-69, 1970-71) 25 years in charge
First Division Championship 1952, 1956, 1957, 1965, 1967
FA Cup 1948, 1963
European Cup 1968
Charity Shield 1952, 1956, 1957, 1965, 1967
* DARIO GRADI
Crewe Alexandra (June 1983-present) 23 years in charge
Promoted to Third Division 1989
Promoted to First Division 1997
FAN'S EYE VIEW: JAMES NESBITT, Actor and lifelong Manchester United supporter
What were your initial reactions after the first game defeat to Oxford?
I always thought they were a bogey team. So I was pretty sanguine about it. Ferguson was very determined, headstrong and passionate. He clearly knew it wasn't going to happen overnight so I was happy to go along with that. But I admired Aberdeen, I liked the idea of a small team doing well. So I thought he's the right man - it was just a question of when it would happen.
At what point did you realise he could be something special?
When he began to break up the team of Norman Whiteside because he was showing the courage that he could make United his own team. Building without bowing to public sentiment.
The night they won the European Cup-Winners' Cup against Barcelona was special. I was doing a play in Birmingham and kept having to run off stage to watch it. When Mark Hughes scored I thought we now have a team who can play great football but also win and refuse to be beaten.
What was Ferguson's greatest moment as United's manager?
The treble. I feel that was him saying "thank you" to United, to Busby, to the fans. Matt Busby was Manchester United but when he won the treble, without eradicating the memory of Busby, he became what we now consider to be Manchester United.
The best game?
For me the best game was the 2-1 win over Sheffield Wednesday at the end of the 92-93 season. Two late [Steve] Bruce goals [the second was in the sixth minute of injury time] turned defeat into victory and propelled us towards the title. Ferguson seemed to make the world bend to his direction. You thought afterwards, "We can win this thing", and in his and Brian Kidd's reaction you just saw how important this was. It was a defining moment.
Who was Ferguson's greatest player?
[Paul] Scholes. But really it's impossible to say. [Roy] Keane was the best and [Eric] Cantona galvanised them. But I think that team would have gone on without him. But also [Ryan] Giggs.
Which was his greatest team?
I thought that the 2003 team [that won the League] were great. And I know Sir Alex feels that it was one of his proudest achievements. He gave those players belief.
I don't believe the whole idea that he rules with an iron rod, although there may be truth in that, because there is no way you can have the commitment and loyalty his players have shown him without them actually respecting him and loving him in a way. He always has a laugh with them, almost like a father figure.
Over a long period: Arsenal.
Best player faced?
By far Thierry Henry. I think he's a brilliant player.
Was he right to sell David Beckham?
I was very sad when Beckham went because I really liked him and I thought we missed him. But I think that things were going on and Alex felt that his authority was being questioned. That was the only time I have really questioned the boss.
Who were his three best buys and worst buys?
Keane, Cantona and [Peter] Schmeichel were the best. Three worst were [Eric] Djemba-Djemba, [Massimo] Taibi and [Fabien] Barthez. He cost us two titles
How long should he go on for?
As long as he wants. He's got at least five years left and probably seven. I think he can go on for a while yet. To keep winning and build three generations of footballers. I did a Q&A with him recently and he said he wants Europe again.
How will he be remembered?
He delivered a team that won with flair, a team that adhered to the United tradition of attacking, exciting football. A team that we could justifiably say was the best and a team that at times left us breathless, at times laughing and quite often, crying. He was the one who turned it into "A Theatre of Dreams".
Interview by Matt DenverReuse content