It's a mighty long way down rock'n'roll, as Ian Hunter of Mott the Hoople wrote in All The Way From Memphis, and at so many points on the journey, you will find Henry McCullough, a sublime guitarist, an innovator, one of the great sidemen.
He came all the way, not from Memphis, but from Portstewart Co Derry, which made the journey somewhat longer and stranger for him, starting as he did with a showband called The Skyrockets, based in Enniskillen, and later Gene and the Gents.
To get from there, to being the guitarist on Joe Cocker's version of The Beatles' With A Little Help From My Friends, one of the most celebrated performances at the Woodstock festival, you had to be good. Indeed, at a time when there were so many virtuoso guitar players out there, you had to be very, very good.
Almost everybody knows the work of Henry McCullough from With A Little Help..., without knowing that it is indeed him playing those searing notes at the start and throughout. He was one of those rare guitar heroes who did not crave the adulation, but who seemed to revel in a certain anonymity - the perfect sideman for the likes of Paul McCartney, who would value his contribution to Wings so highly.
Others would know him at an earlier stage, when he had come through the showband experience and moved, perhaps inevitably, into a psychedelic phase with the Belfast beat group The People.
When The People moved to London to be managed by Chas Chandler, they were re-named Eire Apparent, which somehow did nothing to prevent them gaining a reputation, and touring with groups such as the Jimi Hendrix Experience and Pink Floyd, until Henry was compelled to go in a different direction again - he was busted for possession of marijuana in Canada and sent back to Eire, as it were.
Here it starts to get a bit scary, with McCullough joining Sweeney's Men. It is scary in the sense that Sweeney's Men are regarded as seminal figures in the development of what become known as folk rock, and they may well have actually invented it.
Andy Irvine, Terry Woods, Johnny Moynihan, Joe Dolan (that would be Galway Joe, not Mullingar Joe), and Henry McCullough were, at various times in the late 1960s, engaged in the creation of a nothing less than a new musical genre.
But they didn't talk much about it.
Indeed McCullough was noted for his modesty - a thing so rare among legends of rock, it may be a lifetime achievement sufficient unto itself.
The late Philip Chevron of The Radiators and The Pogues worked with McCullough in 2012 on Sound City Beat, a terrific album of new versions of original recordings by the beat groups, which took McCullough back to his early days with The People - McCullough had also moved back to live in Portstewart, and later that year he suffered the heart attack which led to premature reports of his death, leaving him incapacitated for the last four years of his life.
"He was a delight to work with," Chevron recalled. "Typically he would suddenly announce that he hadn't a clue what he was doing, moments after playing a passage that was definitely a 'keeper'".
Eamon Carr, most famously of Horslips, was also a contributor to that album. Carr had worked with McCullough on the 2008 recording of Poor Man's Moon, a fascinating collaboration between these two founding fathers of Irish rock'n'roll.
Reflecting on the broad sweep of McCullough's career, Philip Chevron put it like this: "it was amazing to me that, for all the monstrous vanities of Irish dancing shows and stadium rock bands, Henry McCullough could boast - but never did - that he not only served with the epochal Sweeney's Men but also played those bloody awesome guitar solos on McCartney's My Love and Joe Cocker's With a Little Help From My Friends, was a member of the Grease Band, played on the original Jesus Christ Superstar, and was the Irish delegation at Woodstock."
Oh yes, there was Jesus Christ Superstar too. And his voice can be heard on Pink Floyd's Dark Side of the Moon, on the track Money, saying "I don't know; I was really drunk at the time".
He had been plagued by his addiction to alcohol, at one point seriously injuring his hand in an accident with a knife.
As he told the interviewer Nick De Riso: "I ended up having to busk about three miles from where I was born and raised. One minute I was playng the Royal Albert Hall, and the next playing on the street for Kentucky Fried Chicken and a bottle of whiskey. I did it to get strength into my hand. I couldn't hold the plectrum, so it was like starting new. Yet once you come out the other side, you feel as happy as I do, and the past doesn't mattter any more...."
He laughed uproariously as he recalled how he and The Grease Band played on Jesus Christ Superstar for a session fee, turning down a percentage of what became a monster hit. But it meant that he had now been in on the ground floor of rock, of folk rock, and of the rock musical.
Henry Campbell Liken McCullough was born on July 21 1943 in Portstewart, Northern Ireland. He died on June 14 at Ballywindelland, Ballymoney.
You may not think that you knew Henry McCullough, but you knew him all right. You knew him well.