Glenn Gould, who died yesterday at the age of 50, was not merely an incredible pianist but one of the finest musical minds of our time.

He shed a unique light on all the music he played, although he was best known, perhaps, for his mannerisms: the out-of-tune vocalizing that could be heard along with his piano-playing in his live performances and can still be heard in his recordings; the pathological fear of colds that made him perform frequently wearing a heavy scarf and sometimes an overcoat; the awkward position in which he performed, from a special piano stool only 14 inches high; the ritual of soaking his hands in warm water for 20 minutes before a performance; the odd accents and frequently eccentric extremes of tempo in his performances; the withdrawal from concert life into semi-seclusion when he was 31, after a public career that had lasted only nine years and made him one of the most famous musicians in the world.

But Glenn Gould will be remembered, when all this anecdotal material is forgotten, for the keen analytic mind, the restlessly probing musical intelligence, that was superbly coordinated with one of the greatest pairs of hands in the history of the keyboard. He will be remembered not only for the new facets he exposed in the music of Bach, Mozart and Beethoven but for the neglected repertoire that he brought back to life: the sonatinas of Sibelius; the amazing Liszt transcription of Beethoven's Fifth Symphony; the Hindemith piano sonatas, as well as those for piano and brass instruments, in which he willingly shared the spotlight (and found a musical modus vivendi--not always easy for Gould) with five other players.

Gould was probably the first significant performing artist to move completely into the electronic age. Although he was recognized as a child prodigy, he did not begin to perform and tour regularly until he was in his twenties. His plan at that time (which he followed with considerable precision) was to perform in public for 10 years and then retire. In 1964, when he stopped playing in public, he announced, "The concert is dead." He limited his performances thereafter to the recording studio, which he called his link to the future, and he later waxed witty about it in an interview with himself published in High Fidelity magazine. "It's obvious," he told himself, "that you've never savored the joys of a one-to-one relationship with a listener," and then interrupted himself sardonically: "I always thought that, managerially speaking, a 2,800-to-1 relationship was the concert-hall ideal." But the real reason for his withdrawal from public performance, he confided, was a feeling that the artist "should be granted anonymity. He should be permitted to operate in secret, as it were, unconcerned with -- or better still, unaware of--the presumed demands of the marketplace."

Gould's studied contempt of the marketplace seemed to pay marketing dividends. Record sales usually dwindle for musicians who stop performing in public, but Gould's have grown steadily through the 18 years when recordings have been his only point of contact with the public. His latest recording, a new interpretation of the Bach "Goldberg" Variations that he first recorded in 1956, sold out in Washington record stores almost as soon as it appeared. It was his 65th recording for CBS, which has kept virtually his whole recorded repertoire in active circulation. Three more long-playing records have been taped by him but not yet released, containing music of Brahms, Beethoven and Richard Strauss.

In an interview with Louise Mach, published in her book, "Great Pianists Speak for Themselves," Gould said, "I do not recall ever feeling better about the quality of a performance because of the presence of an audience. In recording sessions I found that even the presence of one person would make me tend to show off and, to that extent, it actually got in the way of the performance. It meant that I was more concerned with their reaction than I was with what I was doing."

The temptation to show off must have been particularly strong for him because he had one of the most formidable techniques ever heard. But he used it only when he felt it was required by the music. The result of this isolation in performance is frequently a sort of "music in a vacuum" feeling in his recordings -- not exactly the music as written or published, but the music as reflected through one brilliant, quirky mind: 10 precise but unpredictable fingers on the keyboard and an occasional muted voice humming along more or less atonally.

In at least one case, Gould's unconventional approach to music did have negative consequences. His only recording on the organ was issued 20 years ago, containing the first part of Bach's "Art of Fugue." The interpretation, like all Gould interpretations, was brilliant and controversial -- so controversial that the remainder of the work was never issued and, according to a CBS spokesman, never recorded. After 20 years, the truncated interpretation is still available under its original title: "Bach: Art of the Fugue, Vol. I," a small tribute to an artist's refusal to compromise his vision and the marketplace's inability to absorb that vision in its entirety.

Part of the problem may have been that the music public thought of Gould only as a pianist. As a pianist, he devoted much of his energy to the harpsichord repertoire and he brought to his piano-playing the qualities of clarity, dry sound and special attention to rhythmic accents that are more often found in harpsichord performances. He did make a harpsichord recording, quite idiomatic in style, of Handel's first four suites for that instrument. Like the organ record, it never had a sequel.

One result of his activities in the recording studio, as he told one interviewer, was that Gould "fell in love with microphones; they became friends." That friendship deepened and broadened after his retirement from the concert stage, when he became a producer of documentaries for Canadian radio and television. These included programs on music and musicians (Stokowski, Casals, Schoenberg and Richard Strauss, among others), but music was only one of many subjects he approached in his radio work. Sometimes he experimented with quasi-musical audio structures, including taped voices speaking in a kind of counterpoint.

His unorthodox approach to the piano classics evoked mixed feelings in other musicians. In one famous episode, he performed the Brahms D-minor Concerto with Leonard Bernstein, who explained to the audience, before the performance, that the soloist and conductor had irreconcilable differences of opinion on interpretation. The orchestra played in Gould's style on that occasion, producing probably the slowest professional performance the concerto has ever had. Another internationally famous pianist, in a not-for-attribution conversation a few years ago, described Gould's style of interpreting Beethoven as "like murdering your father." But whatever he played and in whatever style, the interpretation was always the result of a profound rethinking of the material and, right or wrong, it deserved and rewarded attentive listening.

Thanks to his rich recorded legacy, it is safe to predict that the world has not heard the last of Glenn Gould. It is also safe to predict that we will never hear another pianist like him.