In 1919, the Swiss conductor Ernest Ansermet, who premiered "The Rite of Spring" and other early 20th- century musical monuments, reviewed a concert he attended in London by Will Marion Cook's Southern Syncopated Orchestra. He concluded his essay by comparing Cook's musicians, including clarinet virtuoso Sidney Bechet, to "those figures to whom we owe the advent of our art," the 17th- and 18th-century pioneers "who made expressive works of dance airs, clearing the way for Haydn and Mozart." He predicted that Bechet's way was "perhaps the highway the whole world will swing along tomorrow."

Ansermet's most prescient observation was to assume that Cook's men were merely heralds of enduring artists like Haydn and Mozart, not the finished product. Within a few years, the world would learn of Louis Armstrong, Duke Ellington, Bessie Smith, Bix Beiderbecke, Coleman Hawkins, Earl Hines, Fletcher Henderson and other astonishing musicians who fulfilled his promise. What most excited Ansermet was the idea of being around for genesis. He was right: That is the most exhilarating aspect of writing about contemporary American music. Until recently, we never evaluated "interpretations" of classics but rather the classics (and misfires) themselves. When I began, it was possible to see four of the '20s icons mentioned above, each still inventive and inspiring. Once, I shook Louis Armstrong's hand, and a jolt went through my arm; I looked into his wonderful creased gray-brown face and tired eyes and thought, I am clasping history itself.

The field should be no less alluring to a jazz critic beginning today, for he or she might have the chance to see historic figures such as Sonny Rollins, Benny Carter, Cecil Taylor, John Lewis, Lee Konitz, Ornette Coleman, Dave Brubeck, Wayne Shorter and more. Still, despite the obvious satisfactions of the job, the question asked most frequently of critics is, How did you become one? The answer is: indirectly. You set out to become a writer and, at some point, you realize your strength is criticism. Writers are admonished to write about what they know, and critics know the arts. If you attend art with scrupulous love, it will yield the world -- every star, every grain of sand.

For me, the process began with the first book to completely capture my imagination, a biography of Louis Pasteur, which convinced me, at 8, that I wanted to be a chemist. After reading other volumes in the same children's series, I decided that being a scientist or a frontiersman or a composer or a Mongol warrior was a mug's game. The thing to do was write their lives; then you could do all of it, and without getting your hands dirty. By the time I got around to biography, however, it was as a corollary to the literary calling that really swept me off my delinquent feet.

The moment of revelation remains vivid. My dad kept stacks of the old, oversized, flat-bound Esquire behind the hat boxes in his closet, and I was now at an age when it was necessary to know why they had been relegated to that shadowy second shelf. So on a night when he was out, I investigated, and in the first issue I opened, I was detoured from the abiding Varga girl by a letter to the editor. The correspondent was annoyed because film critic Dwight Macdonald had complained of Anglophobic casting and conflicting accents in "Ben Hur," when all she, the letter writer, could see was ancient Rome and ancient Romans going about their business.

This struck me as hilarious. My family had taken me to see "Ben Hur" when it opened a year or so earlier, and though I noticed no subtleties of inflection (or any other kind), at least I knew it was a movie. On the other hand, unable to articulate my own doubts about the film, I had cravenly surrendered them before the approbatory consensus in and out of my elementary school class. Rifling through the stack, I located and read Macdonald's review. Then I read his columns in the other issues.

The veil fell from my eyes. Macdonald's irreverence, wit and independence made for a tonic so intoxicating I never recovered. The critical voice was entirely new to me, a razor to cut your way through the suffocating world of received opinion. Having confessed my transgression, I was given the magazines and began to read other Esquire critics (the M brigade: Malcolm Muggeridge, Norman Mailer, Martin Mayer). I discovered book reviews. Upon learning of a certain Edmund Wilson, who remarked that every time he saw an issue of Life he felt like an alien from another planet, I went in pursuit of his books and found a second home in The Shores of Light and Classics and Commercials. Among the numerous critics I devoured were two, Martin Williams and Dan Morgenstern, who spoke to me most compellingly about my other obsession, jazz.

Jazz came into my life with corresponding immediacy one summer in New Orleans, when I was touring the country's perimeters with a dozen or so other 15-year-old New Yorkers. All any of us knew about the deep South were riots, hoses, attack dogs and politicians who spoke -- as Louis Armstrong said of Orval Faubus -- like "uneducated ploughboys." Half-asleep as our bus pulled into the motel court, we peered out the window and stared in disbelief at a wall with three doors: Men, Women, Colored Men.

Later in our room, we decided that Colored Women must have been around the corner, though for a while we wondered whether segregation was different for women. We also determined to hear jazz, chiefly out of curiosity. A newspaper promoted an afternoon concert at a hotel: Emanuel Sayles and His Silverleaf Ragtimers, featuring George Lewis.

Pushing through swinging doors into a small red ballroom, we saw a world far removed from the one represented by the shops we had passed on the way, their display shelves festooned with Confederate flags and pickaninny dolls. Here before us were white and black men and women, cigarettes and cocktail glasses in hand, chatting as though they all belonged to the same country club. The enlightened promise of the gathering was more than matched by the music, a charging, thumping, polyphonic gallimaufry that made my head and heart soar. At intermission, I stood gawking near the bandstand and the pianist, Joseph Robichaux, beckoned me over and asked me about school and how I liked the music, and then called the others over to say hello. We left after two sets, and my feet didn't touch the ground for half a mile. Weeks later I heard Armstrong's 1928 recordings and knew there was no human emotion that jazz could not express and flatter.

Yet when I graduated from college, I deluded myself into thinking I was obliged to write literary criticism of the kind I studied; for despite my conviction that jazz was the age's great musical achievement, I had been infected by a prejudice that regarded it and its commentators as second-string. This was the period when Ellington was declared unfit for a Pulitzer and Miles Davis said that calling him a jazz musician was tantamount to using the N-word. I thought if I could prove myself with an erudite spin on the joys of Dryden, my jazz writing would garner greater respect. Also I experienced a prick of guilt at the prospect of spending my adulthood pursuing the passions of my adolescence. I can scarcely believe even now that people pay me to listen to and write about Louis Armstrong.

For a couple of years, though, no one did pay me, until 1973 when the Village Voice gave me the berth where I remain. The jazz climate has greatly changed over the past 26 years; for one example, the cultural shopping malls that long insisted jazz was popular art and consequently self-financing have opened their doors and purses to jazz repertory ensembles. But the task of writing about music hasn't changed in the nearly 200 years since it became a journalistic sideline. The trick is still to find concrete images to describe and appraise an elusive art and the feelings it engenders. Among musics, none is more elusive than jazz, which is largely improvised and fleeting -- except when recorded.

Jazz solos that are heard only once disappear as completely as the concerts George Bernard Shaw reviewed in the 1890s. But recorded jazz will last as long as the scores that generated those concerts. Armstrong's recorded performances of the 1920s, and those of other jazz musicians, are often transcribed and turned into scores for repertory performance. There is a crucial difference, though. A musical invention by Armstrong cannot be transcribed in full; qualities that make it jazz and make it great -- the rhythmic panache or swing, the luminous blues timbre -- defy the limits of notation. Jazz scores can only advance what musicians learn from auditory experience. Even so, at century's end, jazz transcriptions are routinely the basis of concerts; never before in jazz history have critics found themselves reviewing so many interpretations, recreations, facsimiles, variations and revisions of the classics.

How distressing is this? Not very. Every decade has brought seismic shifts in style and idiom, followed by heated debate. In a hundred years jazz has never stood still long enough for its past to catch up and consume it; that's one reason many fans are disillusioned when the jazz styles of their youth are radically revised. In the '90s, the issue is, as it is in many of the arts, an obsessive recycling of the past -- the recent New York JVC Jazz Festival was primarily devoted to the playing of classic jazz.

Old issues for classical music have become topical ones for jazz: How much license should a conductor have? Are records more binding than scores? Will classic jazz and the institutions that support it leach out innovation and originality? Where will jazz go -- how will it reflect, as it always has in the past, parallel developments in popular, academic, international and avant-garde musics? These are vital, healthy questions. Only when all debate has ceased will jazz become a museum music, and the boundaries of genesis fixed for all time. I see no indication of anything remotely like that happening in my lifetime.