BOOK REVIEW / The pianist who played by himself: Glenn Gould: Selected Letters Ed. John P L Roberts & Ghyslaine Guertin OUP, pounds 20

IF YOU'VE ever sung in a choir, hung around backstage with an orchestra, or sat on the tail of a musician's car, you'll have seen the stickers: Keep Music Live, they say, and they have the same sort of visceral moral appeal as exhortations to save the whale or to quaff real ale. Protect something endangered, treasure the real in a world threatened by fakery.

You wouldn't have wanted to follow Glenn Gould's car too closely ('his delight in singing at the wheel . . . led to minor accidents'), but if you had you wouldn't have seen the sticker. One of the greatest pianists of the century, Gould was the enfant terrible who denied that the live concert had a future in the age of recording.

He retired from the concert platform in 1964, continuing to make records until his death, aged 50, in 1982. His status as guru was consolidated by The Glenn Gould Reader, a posthumous collection of critical and occasional writings published in 1984; it is confirmed by OUP's publication of these letters, boring, infuriating and fascinating by turn.

There are letters here that could interest only the serious Gould freak. Writing to Rudolf Serkin in 1961, he thanks his fellow pianist for an (unspecified) gift. The letter offers an iota of intimacy with its mention of Gould's racoon coat, 'classic vintage 1925 which has been handed down in our family until all, except me, were ashamed to be seen in it'. This is just the sort of detail fans cherish. Endearing personal eccentricity (singing along as he plays the piano, wearing winter coats in summer, disliking the Appassionata sonata of Beethoven) only increased the Gould mystique. On one level, this collection feeds this 'Gould phenomenon', as the editors put it.

Gould's eccentricities were, however, more than the classic idiosyncrasies of genius. He thought his ideas through and lived them out, most notoriously when he stopped performing in public, thus inventing the idea of the recording artist.

As we learn from the letters, a number of things drove Gould out of the concert hall. Coughing. Applause. Fidgeting. Theatricality. These imperfections suggested to him that the recording studio was the better home for artistic integrity, for what he calls in one of these letters the artist's 'solidarity of the ego'. Suspicious of the 'misalliance' between artist and audience, he deplored the over-dependence of many musicians upon extra-musical stimulation. Recordings offered freedom from all these distractions. What is more, through the mechanism of editing, one had the capacity to construct the ideal performance from a number of takes.

Ultimately, Gould was to express this in a fantasy of individual omnipotence, where not only the artist had control over his end product but the listener also could construct out of the recordings available to him his ideal performance - eight bars of Klemperer here, 10 bars of Karajan there. Nostalgia for the lost world of domestic music-making is given a ghastly twist, and music becomes a matter of knob-twiddling non-communication: each man is an island.

It seems odd at first that the letters should reveal the pianist Artur Schnabel to have been one of Gould's great heroes - Schnabel, whose famous recordings of late Beethoven sonatas are full of missed notes and fudged tempi. But then, in playing against the limits of his own technique, Schnabel was gesturing towards an abstract ideal performance. The difference for Gould was that he thought technology could help that ideal to be achieved.

Gould was in many ways right about the future of performance. We are now awash with recorded music, and it forms the backbone of most musical experience. But the economics of music still demand the concert. This is not just a matter of the musicians' livelihood as concert performers, as the editor here suggests. The concert is also a legitimating spectacle and a marketing device. If the concert featuring tenors Pavarotti, Domingo and Carreras in the Baths of Caracalla in Rome can be billed as the concert of the century, then the CD and video become a means of participating in a historic event.

Gould misread what music as a commodity meant for the concert tradition. A more significant fault was his insensitivity to the electricity of live performance.

The essence of performance is community - the community of the players, the communion between performers and audience, the continuity of re-invented musical tradition. Solo pianists often have a distinct and alienated attitude towards performance (like Richter playing in the dark).

Glenn Gould, we learn, preferred to conduct his personal life on the telephone - or even, indeed, by letter - rather than face to face. It's hardly surprising, then, that he liked playing for microphones.