The bones of Grainger's life are easily given. Born in a Melbourne suburb in 1882. First public appearance as a pianist in 1894. Student in Frankfurt from 1895. Moves to London in 1900 and soon becomes a leading figure in the English folk-music revival. In 1903 studies piano in Berlin with one of the all-time giants, Ferruccio Busoni. And then, after settling in the US in 1914, a career spent in trains and boats through a gruelling concert schedule that only someone with Grainger's unquenchable energy could have sustained. In his last decade, when he was riddled with various cancers and his strength was failing him, Grainger was still travelling, even as far as his native Melbourne, where he supervised work on the Grainger Museum he had founded in the Thirties. He died in 1961, willing his entire artistic legacy, and his skeleton, to the museum.
Like many people, I grew up knowing at least one piece of Grainger's Country Gardens from constant broadcasts before I'd even heard the name of Beethoven; and Grainger is still one of the "classical" composers whose music you're most likely to find yourself humming, even if you don't realise you are. "Shepherd's Hey", "Handel in the Strand" and "Mock Morris" have all entered a kind of national repository of music that is recognised instantly.
But Grainger was no mere tune-smith. Years before Debussy began to work with whole-tone scales (omitting semitones), the 15-year-old Grainger was experimenting with them in his own music. This open-mindedness continued throughout his life: as an old man, he was still trying to perfect a Free Music Machine, intended to produce music that was as unfettered as the sounds of nature.
Grainger's rejection of what he saw as the dead hand of the Germanic tradition also extended to its forms. The London-based Australian pianist Penelope Thwaites explains quite what his radicalness involved. "There was a bigness about Grainger and a very daring free-thinking. For instance, he threw out sonata form completely, so bang go all the concertos, symphonies, string quartets and all those things that make you a `serious composer'. Then you have to try to figure out some way of constructing a longer work. He didn't entirely succeed, but then he made up for it in the sheer intensity of what he could produce in two or three minutes."
It's the intensity, and easy-going but compressed joyfulness, that make much of Grainger's music so compelling. And at other times his work has a visionary quality that few other composers achieve, in pieces such as "The Lonely Desert-Man Sees the Tents of the Happy Tribes," the muscular "English Dance" ("as if the whole population were dancing", said Gabriel Faure) and the polyrhythmic ballet The Warriors, a riot of contrapuntal complexity, requiring three conductors to co-ordinate it.
Now, nearly 40 years after his death, Grainger's music seems poised for a genuine revival. A feature film based on his life will be released next year. The Colchester-based company Chandos has taken the courageous step of recording all of his output, on no fewer than 25 CDs, which for the first time will make clear the full range of Grainger's unpredictable genius. Chandos is currently up to the ninth release in the series. I have just listened, twice, to all nine in a row and am left with a feeling of heady exaltation - this is genuinely thrilling music, in performances that must be just about the best Grainger has ever enjoyed.
Now, after a year of planning, Thwaites has organised The Grainger Event, a compact extravaganza spread over the weekend of 7-8 November in St John's, Smith Square, London. It brings together performers and scholars from around the globe wherever Grainger was active - Britain, Australia, America and Scandinavia - in performances of more than 70 of Grainger's works, concluding with a multi-piano gala concert.
Thwaites outlines what she is trying to achieve. "I'm extremely keen that people are intrigued to come to St John's because they probably won't have such an experience again in their lifetime. To have all these people together and to have such a range of music simply hasn't been done before. Anyone who comes to it will get a kaleidoscopic view of Grainger.
"For instance, Alessandro Servadei will be giving a kind of walk through the Grainger Museum with slides and archive material. Nikki Beckett has built a replica of Grainger's Free Music Machine. Stewart Manville from the States, who married Grainger's widow, Ella, will be here with us. Bo Holten from Denmark, who often conducts the BBC Singers, is coming to do a choral workshop with them and the audience... we're going to get the music and let rip!
"In the past Grainger's been treated to a blandness, a smoothness - even, dare I say it, a wistful Englishness. There's got to be a rough edge, a lustiness, an undercurrent of a sharp, painful feeling. Grainger identified very much with people's sadnesses and sufferings - which, obviously, is where a lot of folk music has always come from, as people express what they feel."
The contradictions of such a personality are baffling to anyone approaching from the outside. How can the composer of such heart-warming music be reconciled with the man who enjoyed what he called "whip-lust" or who could write, for example, of the sexual tingle he felt when he dreamed of fish-hooks tearing through a woman's breasts? Grainger himself attributed the origins of his sado-masochism to the regular whippings he received from his mother when he was a boy. By the time he reached puberty, the thought of these beatings was an irrevocable stimulus of sexual pleasure.
Thwaites has an unusually perceptive explanation for such apparently aberrant behaviour. "There was real tragedy in the family. My attitude to the whole thing is one of compassion, and that is something that has been spectacularly lacking in the way people write about Grainger. The real point is that his mother, as a young and wilful person, leapt into a marriage for which she was totally unprepared; and she had no idea that she was marrying an alcoholic. She didn't discover that she had been infected with syphilis until after he had knowingly accomplished it.
"This must have happened a great deal in those days, and women were expected to get on with it. I feel an enormous compassion for her situation; she was obviously a very strong person, but she was then totally isolated. She could not continue her relationship with her husband. She could not contemplate a relationship with anybody else. And she couldn't talk about this to anybody until she suddenly decided to confide in her son, who was verging on puberty and who then took the whole load on his own shoulders and said: `I'm going to look after you until you die.' There's something so touching about that, and it's also entirely understandable that, with all these avenues closed off and all that pressure, he's got to work off steam somehow. There's so much tragedy in many composers' lives, and what matters is what they do with it. He turned it into extraordinarily stirring and beautiful music."
The Grainger Event - 7-8 November, St John's, Smith Square, London SW1 (0171-222 1061)