Master of the Oo and the Trimba, exponent of the drum-and-ostrich- feather -

I can still smell the musty damp of the basement of Dobell's jazz shop on Charing Cross Road. I can still feel that adrenalin surge, known to all record-retentives, when you finally hold in your hands the LP sleeve you'd given up hope of ever seeing. Now comes that heart-stopping moment when you are convinced the assistant will rummage everywhere before saying he can't find the record that goes with the sleeve. But no, it's all right, the record is there; I hand over my pound note and take possession of a copy of the long-deleted Esquire LP by New York street musician Moondog, whose music offered what was then a unique amalgam of Amerindian percussion, jazzy riffing, European counterpoint and troubadour balladeering.

That was nearly 30 years ago. Over the next few years, I learnt every track by heart: "A Duet: Queen Elizabeth Whistle and Bamboo Pipe"; "Tugboat Toccata"; "Ostrich Feathers Played on Drums". This is the sound of New York, some of it literally so. Many of the tracks were recorded on the streets where Moondog made his living in the 1940s and 1950s. Even the names of the instruments he played - the Oo ("a triangular, stringed instrument struck with a clava"); the Trimba ("a triangular-shaped drum") - took on magical significance.

Having no idea of Moondog's whereabouts, I was astonished when, in 1969, Columbia Records issued an album of Moondog performing his works with a 40-piece symphony orchestra. A long way from playing his drums to his dog in a shop doorway. Then I lost track of him altogether. In 1991, the New York recordings I'd bought on LP reappeared on CD, and I assumed that was it. The music still sounded vibrantly fresh, but Moondog was now digital history. Perhaps he was even dead: life on the street in New York can't be easy.

But not only is Moondog not dead, he is still, at 79, composing and performing, and he is in London for a single concert. This was both a chance to interview him and, more importantly, the opportunity to get his signature on that old LP sleeve.

The important business over, Moondog tells me about his life. He was born Louis Thomas Hardin in Kansas in 1916, where his father was a travelling minister. His father's calling gave him his first musical memory, albeit an unexpected one: "When I was about six years old, my father took me to a convention on the Arapaho Indian reservation. I sat on Chief Yellow Calf's lap and he let me play the tom-tom while they were dancing. The Arapaho had the two beats: the running beat..." (he taps out a rhythm on the table) "...and the walking beat. Those two beats have stayed with me ever since, are still in my music today."

Moondog lost his eyesight at the age of 16, when a dynamite cap exploded in his face. "You lose one sense, the others become stronger as a result. At the Iowa School for the Blind, I heard my first Beethoven and Wagner, and it made a great impression. At the school they taught me harmony, but they didn't teach counterpoint. I read a book that said, 'You'll never be a composer unless you master counterpoint', so I studied by myself."

His ambitions awakened, Moondog determined to make his own music, but in Iowa his ideas fell on stony ground. In 1943 he went to New York. "Why? Because it was there. I knew I had to make it there if I was going to make it at all, and New York gave me opportunities I would never have had anywhere else. I met the great conductor Artur Rodzinski, who allowed me to attend the New York Philharmonic's rehearsals, and I met Leonard Bernstein. I had no income, so I was posing in art schools for a while, then the Philharmonic raised some money to pay my rent. In 1949 I started playing drums in doorways at night and made my living that way."

It was at about this time that he adopted the street name Moondog: "I thought I was being original, but I wasn't. Alaskan Indian mythology has a rainbow over the moon called Moondog, and there's a giant in the Eddas called Moondog. And did you know that the Beatles once called themselves Johnny and the Moondogs?"

In 1952 he made his first recording, an EP called On the Streets of New York. And life on the street became part of his music, whether playing a duet with the horn of the Queen Elizabeth as it docked, serenading his dog, or playing and reciting his poetry for the friends who gathered at his pitch. "Performing in doorways was the only way to present my music to the public, but for playing on the streets I needed drums down close to the ground, so I used to design my own instruments and had a cabinet- maker put them together. In those days there wasn't any anxiety about the rainforest, and I had my instruments made out of Honduras mahogany. I still have a couple of my trimbas, but the rest I gave away when I left New York in 1974."

What took Moondog away from New York was an offer from German radio to conduct performances of his work in Frankfurt. As the Columbia album with the 40-piece orchestra suggested, Moondog sees himself as a composer in the European tradition: "I feel closer historically and culturally to Europe. This is where it all happened. [But] the American Indians are still a big pull for me, and I combine European classical forms with the drumbeats of the Indians."

Aesthetically, Moondog is in many ways a conservative: "Musical modernism is a nightmare that will pass, a big detour that leads into the swamps." Yet his conservatism has certain off-the-wall idiosyncrasies. "My piece Invocation is a 16-part canon on one note, and the note is the kind of drone the Tibetan monks use," he explains. "That piece suggests the dead are speaking to the living, or perhaps it's a conversation between the living of this galaxy and the living of some other galaxy. Thought is faster than light, it's instantaneous over trillions of light years. Another piece, The Cosmicode, shows the infrastructure of the universe. It proves that contraction must precede expansion, it proves the two-directionality of time, and it proves cause-effect inversion. Can you imagine that?"

Not yet, Moondog, not yet. But maybe by next weekend. On Saturday, as part of Elvis Costello's "Meltdown" festival at London's South Bank Centre, Moondog conducts - banging on a big bass drum - performances of his work by a group of musicians with whom he has developed a close working relationship. They include soloists John Harle and Danny Thompson (ex-Pentangle) and groups London Brass and London Saxophonic. Moondog's catalogue of works is immense, including 81 symphonies, dozens of pieces for sax ensemble, 16 "Troikans" and a fistful of songs, to say nothing of the 1,000 poems he has just collected for a volume called Moondog Millenniad. It's a long way from the street corner to the Queen Elizabeth Hall, but it's a journey that describes the life of a truly unique musician.

n Moondog and guests will be at the Queen Elizabeth Hall, London SE1 at 3pm on 1 July (booking: 0171-928 8800)