SOME years ago, Al Hirschfeld returned home from a run-through of Ariel Dorfman's "Death and the Maiden." His wife asked him what the play was about. "Germany after the war," he said. The play was about Chile after dictatorship, but Hirschfeld had not been paying attention to the plot. He saw Gene Hackman onstage gagged and tied to a chair and assumed he was a captured Nazi. It didn't really matter anyway. Hirschfeld was too busy drawing what was happening onstage to notice.

Does that sound like a contradiction? In this case it is not. As an artist, Hirschfeld, who died at 99 on Monday, cared about visual cues: gestures, mannerisms, the way an actress dashed across the stage or cocked her head while he sat in the dark of the theater jotting shorthand impressions to take home and translate into drawings. Call them abstractions of the drama, which became loopy lines, dashes, dots, curlicues and crosshatches.

What kind of artist was Hirschfeld? He was a genius at capturing likenesses in a few serendipitous strokes - as good as they got, week after week, since the 1920's, turning the viewing of his work on this page into an American ritual.

But what really separates him from other caricaturists is the vitality and suppleness of his line, an abstract matter. I recall once walking around the Metropolitan Museum with Roy Lichtenstein, another kind of Pop caricaturist, who spent half an hour noting the light and shade and color of a Manet without ever referring to what the painting was about. "A funeral?" he said, when I pointed to the title. "I never noticed." Which is to say, every good caricaturist is a closet abstractionist.

Line as movement - prancing, skipping, twisting and dancing - was the vehicle through which Hirschfeld conveyed the adrenaline rush of live theater and his absorption in the here and now, resulting in art that looks eternally, uncannily fresh. Glance at the drawings he did of Bill Robinson, Bojangles, tap dancing in "Blackbirds of 1928," or, from the same year, Basil Rathbone in "The Command to Love" and you will see they would look perfectly natural on the front page of today's Arts & Leisure. They do not provoke nostalgia, the way photographs of the past do. Hirschfeld's career encompassed the years of Norman Rockwell's, but Rockwell's art, notwithstanding its skill and charm, looks dated. Hirschfeld's doesn't.

"If you ask me what I got from him," Jules Feiffer said last week, "it's that I want people to look at my own work, as they do at Al's, and feel that my drawings represent the moment; that, like Al's work, the work never happens in the past tense."

Hirschfeld himself, of course, happened onto the scene in the distant past. Born in St. Louis, he arrived in New York at 12 when it was still possible, he said, to take the Amsterdam Avenue streetcar to the end of the line and be in farmland, which is what his family did: they walked past apple orchards until they discovered an apartment for rent on the top floor of a house on 183rd Street for $4 a month. He began to study at the Art Students League, making academic sculptures (sculptures, he liked to joke, were "drawings you fall over in the dark"); then he supported himself as an art director for silent films.

Like other aspiring American artists, he looked to Europe, buying passage on a steamer for $65 and lodging in a cold-water flat in Paris, where he earned cash tap dancing and playing the ukulele. There are some watercolors he did a little later, during the 1920's, while traveling in the Soviet Union and Iran, that suggest a taste for Delacroix. A few of his caricatures of actors, drawn once he returned to New York, toy with high-modernist styles like Constructivism and Cubism.

He passed through a political phase. He made lithographs for The New Masses magazine in a knockabout style consonant with leftist taste back then. But dark political satire and working-class salutations did not come naturally to a gentleman like Hirschfeld, whose milder demeanor led him toward comedies of customs and manners. In this respect, his predecessors were not Daumier and Rowlandson. They were Max Beerbohm and Miguel Covarrubias. Covarrubias, his great friend, was the stylish illustrator for Vanity Fair. Beerbohm, the eminent Victorian, although always sharper and more cynical than Hirschfeld, moved among the statesmen and politicians whom he caricatured. You see that familiarity in his work, the way you see that Hirschfeld was a man of the theater, not just someone who went to it.

Covarrubias inspired Hirschfeld to visit Bali in the early 1930's, where light, Hirschfeld said, washed out color and reduced everything to lines. Asian artists understood line best, he concluded: artists like Hiroshige and Utamaro, calligraphic masters of elasticity and elegance.

But like all originals, Hirschfeld absorbed this and finally went his own way. "He was the most original caricaturist of the century," the caricaturist David Levine told me last week. "His line was like embroidery, decoration. I mean that in the best sense. The rest of us rely on conventions. Al had one of the only unique styles in the history of art."

He had the unnerving ability, Mr. Levine said, even into his 90's, to describe a scene he had witnessed 70 years earlier, down to facial gestures. His art was a kind of mental editing of perfectly remembered details: the tactful compression of information. "I did a drawing of Jimmy Durante and I left the nose out," Hirschfeld noted proudly. When he tried to make a nasty caricature of the producer David Merrick, not his favorite person, dressed up as a Santa Claus, Merrick liked it so much that he used it to illustrate his Christmas cards.

Was kindness a weakness? Only if you think of caricature in a mean and narrow vein. Art, including the art of popular illustration, takes many forms. Aubrey Beardsley was a different sort of illustrator, all decoration and wicked charm. Hirschfeld was about decoration but also the joy of life. This made his work a useful antidote to the front page headlines of the Sunday newspaper. Within the courteously stodgy New York Times, Hirschfeld's courteous effervescence seemed outsized.

The escapist game of planting Ninas in his illustrations, a lark he contrived when his daughter was born in 1945, became a national pastime. It had the useful effect of holding readers' attention while functioning as a secret password for Times aficionados everywhere. My wife told me that as a girl in upstate New York, she felt she had gained entree into a bigger, exciting world when her father showed her what the mysterious number beside Hirschfeld's signature signified.

HIDING names, a Surrealist's device (that's more highfalutin than Hirschfeld imagined it, I'm sure), was like everything else in his art, a wink. The New Yorker had Peter Arno's babes to lighten Hannah Arendt's prose. The Times had Hirschfeld's charmed vision of the Great White Way to lighten up the Gray Lady.

It was his good luck and ours that his years coincided with the heyday of American theater - by the end, he was just about the only glamorous remnant of that bygone age. You see in "The Line King," the 1996 documentary about Hirschfeld by Susan W. Dryfoos (Times History Productions), how painstakingly he arrived at this impression of glamour. Bent over rough pencil sketches at his drawing board, Hirschfeld traced each line inch by inch with his pen dipped in ink until those pirouettes and curves looked as if they had happened all at once. Like the theater, the impression of rapid motion was an illusion.

I think motion was his ultimate subject, the motion of a conductor's arm sweeping upward, the motion of a dancer twisting sideways, the motion of an actor prowling the boards, which is why his work conveys immediacy - and why he enjoyed most of all "glandular" types, the ones, he said, who "don't close the doors, they slam them": clowns like Chaplin and Bill Irwin, Zero Mostel, Liza Minnelli and Carol Channing.

His subjects said Hirschfeld's caricatures captured what even they couldn't see in themselves, a livelier self, which inspired them to imitate how he saw them. Maybe so.

Another way to put it is that he projected onto everyone a vivacity and panache that we all wish we had.