Mention the name Brian Clough to Sunderland fans of a certain vintage, and the phrase "the greatest manager we never had" could well figure among the responses.
Clough, a Roker Park favourite thanks to his prodigious goalscoring before his career was cut short by injury, followed his retirement with a stint as youth-team coach before the club cast him aside in 1965 - and was never to return to Wearside.
Instead the forthright Teessider went on to win league championships and European Cups with Derby County and Nottingham Forest, much to the disappointment of a generation of Sunderland supporters.
Sunderland-born Jonathan Wilson, author of a new Clough biography entitled 'Nobody Ever Says Thank You', grew up with the aura of 'Old Big 'Ed' during his childhood.
"It was something I never understood, why Clough was one of my dad's favourite players," Wilson told BBC Look North.
"When I was a kid and my dad would talk about him, I assumed he played about seven or eight years here, and scored hundreds of goals, when in fact he actually played for about 18 months.
"I think Clough to an extent symbolised what might have been - the team of 1962-63 looked dead set for promotion when he got the injury [the club missed out by a point without Clough's firepower].
"The other side of that is not only what he might have been as a player, but also as a manager as well.
"He took the youth team to the semi-final of the FA Youth Cup, but the club got rid of him, and I think Clough had become very difficult by then.
"You speak to Jim Montgomery, Charlie Hurley and Stan Anderson who were in the team at the time and Clough would be slagging them off in the tunnel at half-time, frustrated at what he thought he could do better."
By twist of fate, it is one of Clough's disciples that currently occupies the manager's chair at Sunderland.
Martin O'Neill spent 10 years on the right for Nottingham Forest before departing for Norwich City in 1981.
However it was not until Clough arrived at the City Ground in 1975 that club and player flourished - winning promotion from the Second Division before lifting the First Division championship the following season.
O'Neill also played a key role as Clough's side progressed in their European Cup adventures and although he missed the first of the triumphs - relegated to the bench to accomodate £1m signing Trevor Francis, he was part of the team that beat Hamburg in the 1980 final.
Since entering management the Northern Irishman has enjoyed success - lifting the League Cup twice at Leicester City and taking Celtic to a Uefa Cup final - and as a boyhood Sunderland fan has been a popular appointment.
"They both have that same intensity in many ways," Wilson continued.
"When you're in an O'Neill press conference, you sort of have a sense that you never quite know what is coming next.
"He's clearly a very deep thinker about the game, a very intelligent man but there is a slight brittleness, a sense he can be quite caustic at times.
"That could just be his character, but that ability to keep players on their toes with that occasional harshness is useful."