The song was all to sean-nós giant Joe Heaney, whose life is now being brought into focus, writes Siobhán Long

With a face carved straight out of Mount Rushmore and a voice as straight as an arrow, Joe Heaney was a giant among sean-nós singers. He possessed that essential quality: the ability to not so much inhabit a song as let it inhabit him, allowing it to transform every cell of his being while its notes caused ripples across the airwaves.

Liam Clancy, long a champion of this Connemara singer, summed up Heaney's peculiar iridescence, after watching him still the crowds at Newport Folk Festival in the US: "When he got immersed in a song, he became possessed by that song. And it was like he was a medium. It wasn't an individual that was singing. It came out of everything that had gone before him. And anybody who ever watched him singing got that sense of not just the individual but the importance of what he had come from."

Liam Mac Con Iomaire has undertaken the leviathan task of attempting to pin down the essence of this Confucian conundrum who was Joe Heaney. Seosamh Ó hÉanaí: Nár Fhágha Mé Bás Choícheis a sweeping biography of the singer that coaxes the covers back from Heaney's complex life, and while, as with all biographies, there are questions about whether he has truly captured his subject, he has certainly succeeded in bringing together a vast conglomeration of commentary, documenting the quotidian as well as the crucial in Heaney's picaresque life.

Luke Kelly, Willie Clancy, Seamus Ennis, Ronnie Drew, Paddy Glackin, Tom Munnelly, Peggy Seeger and Ewan MacColl are just some of the commentators whose stories are writ large across this Heaney canvas. One of the most consistent themes running throughout the book is Heaney's indelible sense of himself and of the importance of his home place. Despite being addressed by three different names - Joe Heaney by English speakers, Seosamh Ó hÉanaí by the vast majority of Gaeltacht denizens, and Joe Éiniú by his Connemara neighbours - Heaney's identity was unwavering.

Having grown up in Carna, deep in the belly of south Connemara, in a barren, poverty-stricken land, Heaney travelled widely with his songs, and spent the final years of his life in Seattle, where his disciples gathered round him in their hundreds. His singing was the exemplar that shone a pathway for so many sean-nós singers who came after him. As Ewan MacColl remarked, Heaney was the voice, just as Willie Clancy defined the pipes and Michael Coleman the fiddle.

"As well as being a singer, he was a great performer", Liam Mac Con Iomaire remarks, while admitting his own sense of intimidation when he was in the presence of this colossus, who died in 1984. Heaney's reputation for cantankerousness kept many of his acolytes at arm's length, but it didn't prevent them from soaking up the passion of his singing, whatever his disdain for social niceties.

"He was so sure of himself from quite a young age, I believe", Mac Con Iomaire adds. "He had so much respect for, and demanded respect from others, for the songs he was singing and the background to them, that he wouldn't tolerate anyone speaking while he sang. He would stop if they did that, but the fact was that he commanded, demanded and deserved respect. We have an expression in Connemara, 'omós don amhrán', respect for the song - no matter who's singing."

THIS HEANEY BIOGRAPHY is accompanied by a magnificent CD, containing 18 songs, many of them taken from the archive recordings of the late Proinsias MacAonghusa, and bequeathed to RTÉ by MacAonghusa's wife, Justice Catherine McGuinness. These recordings alone will be hotly pursued by sean-nós singers the world over; they are the Dead Sea scrolls of traditional music.

Anyone with even a semblance of a beating heart couldn't fail to be moved by Heaney's version of Caoineadh Na dTrí Muire; his wide-open delivery, unadorned by redundant decoration, akin to the mournfulness of the pipes at their lung-filled best.

Joe Heaney's formative years were spent in a place where the indigenous desire to sing out loud was not only encouraged, but valued as a form of therapy, a (far cheaper) precursor to counselling. Much as Aboriginals sing their beloved landscape into existence with their songlines, for the singers who surrounded Heaney in Carna, their songs were nothing more and nothing less than an integral fabric of life, not some kind of cultural affectation for the benefit of the outsider.

"Singing was an integral part of our social life," says Mac Con Iomaire, a native of Casla in Connemara himself. "Joe's mother's people were famous storytellers, and he had countless songs to call on. And there's no doubt about it, these songs of our past kept our people alive in all the Gaeltacht areas. Even though they were economically poor, they had cultural riches when they visited one another's houses.

"Seamus Ennis, who visited Joe in Carna after seeing him perform at the Oireachtas in 1940, used to visit these houses and cycle home at four and five in the morning!"

Joe Heaney led a colourful life. Having married Mary Connolly of Carna, with whom he had four children, the couple separated in 1951 and he took to the road, spending time in Southampton, London and Dublin (where he was a stalwart of O'Donoghues along with The Dubliners) before ultimately moving to the US in 1975, at the behest of the Clancy brothers.

He found a ready and enlightened audience in both New York and Seattle, who savoured the chance to hear sean-nós songs, replete with their fulsome back-stories, from a singer who made no apologies for his particular plainsong style. Lauded across the US, Heaney was given the National Heritage Award for Excellence in the Arts in 1982, just after his arrival in Seattle, where he taught at the university.

Producer Kenneth Goldstein summed up Heaney's appeal after his performance at the Philadelphia Folk Festival in 1973: "Through his voice, his songs and his centuries-old yet extremely viable traditions, he presents himself as a rare artist, a performer so accomplished with his material that the audience is elevated and held from beginning to end.

"All this was without instruments, stage gimmicks or the conventional accoutrements of show business."

HEANEY WAS A man who knew no fear. He could balance the fine art of sean-nós with a surprising openness to the possibilities of contemporary composition.

He was a linchpin of John Cage's cutting-edge composition, Roaratorio, his so-called "Irish circus" (based on Joyce's Finnegans Wake), in 1979, along with Seamus Ennis, Paddy Glackin, Matt Molloy and Peadar Mercier. Despite his formidable reputation for the pure drop when it came to singing, Heaney wasn't averse to engaging in this tower of Babel, a milieu about as far removed from Carna as the wilds of Borneo or the depths of the Grand Canyon.

Peggy Seeger, a singer who's no stranger to a transcendent love song herself (being the subject of Ewan MacColl's sublime ode, The First Time Ever I Saw Your Face), spoke of Heaney settling into "the old Gaelic songs" as he would "into the arms of a lover". Singing was what defined the man; it was the impetus that propelled the blood through his veins.

Liam Mac Con Iomaire has gone a long way towards capturing that essence, even if, one suspects, Heaney himself would be nonplussed by such attention to the minutiae of a life lived at times wildly and, at others, wisely.

Seosamh Ó hÉanaí: Nár Fhágha Mé Bás Choíche, by Liam Mac Con Iomaire, is published by Cló Iar Chonnachta