Afew Wednesdays ago late in the afternoon, a group of teenage girls came bounding out of Colony, a fluorescently lit music and record store at 48th Street and Broadway. They formed an impromptu little circle and began to sing at a volume that was hard to ignore, even during a rush hour that had turned the blocks around Times Square into a honking jumble.

Paul Simon stood about 10 feet away. Wearing a baseball cap and a weathered leather jacket, he went unnoticed by everyone except a guy selling cigarette lighters from a tray ("You smoke, Paul?"). He had just spent a ruminative hour in an interview, sifting through his life and music, and now he was heading to a screening of the new Harry Potter film, which he would see with one of his young sons. He was running late, but when the spontaneous concert began, he paused, then tilted his head slightly and listened to a couple of sloppy verses.

"That's cool," he said quietly. He was beaming.

The song was kiddie R&B stuff, helium compared with the heft of just about anything Simon has ever written. But he didn't care about the song. What captivated Simon was the unglued spirit that had moved these sidewalk Supremes to their full-throated warble.

"That's the power of music," he added, nodding.

He took in another verse, grinned some more and then got a little wistful.

"My music used to have that power," he said, matter-of-factly. "Now it has a different kind of power."

Another pause. Simon is a deliberate thinker who would rather get the sentiment right than express it in haste.

"When you're young and your music has that power, you think you'll have that power forever." He shrugged a little. "But the truth is, you don't."

For any singer-songwriter, an award that honors a career, rather than merely a hit or an album, is sure to dredge up some big fat unnerving questions about the past and present. But Paul Simon probably didn't need a plaque from the Kennedy Center to kick-start the deep thoughts. The guy was born to contemplate, and since the mid-'60s, when he and Art Garfunkel had fans in turtlenecks pondering the sound of silence, he has turned those cogitations into reams of melodious poetry.

Early on, he penned songs of such lyrical richness and ethereal harmony that they still resonate like prayers on wax. He told stories ("The Boxer"), inspired ("Bridge Over Troubled Water") and sent the country in search of a campfire to sing around ("Homeward Bound"). His solo career, which began in 1970, produced some high-profile duds, like 1983's "Hearts and Bones," and his catastrophic Broadway musical, "The Capeman," which closed soon after it opened in 1998. But Simon's creative wanderings paid off in hits ("Kodachrome" and "Loves Me Like a Rock," to name a couple) and critically acclaimed global adventures (most notably "Graceland"). Along the way came original hybrids of jazz, zydeco and reggae. His last album, "You're the One," sold about half a million copies -- well short of his bestsellers -- but received a Grammy nomination for Album of the Year.

It's a canon that places him among the great American songwriters in the 20th century. So why oh why is Paul Simon sweating the 21st?

"When you get an award and it's a significant national award, it places you in a perspective," he says, sitting on a sofa in his office in midtown Manhattan. "I think it's interesting to stop and actually look at that perspective." But he noted, a little solemnly, "It's not necessarily my perspective." He stirred himself a little to focus on the upside. "I think it's fun to take a minute and say, 'Thank you very much. I appreciate the affection.' "

He may have to get used to it. The people who run the Grammy Awards just announced that Simon and Garfunkel would receive a lifetime achievement award at the next ceremony, in February. (So will Etta James, Tito Puente, Johnny Mathis and Glenn Miller.)

Simon is still writing, though at what he describes as a painstaking pace, and the frisson of crafting songs that matter to the masses is alive and well, roughly 45 years after he first entered a studio. (He is now 61.) He realizes it's time for a bow, and he'll take one with gratitude. But he hopes the theater of his creative life has more acts to come.

"I'm as patient as I can be with it," he says of recent songwriting efforts. "My instinct is to hurry, but it won't do me too much good to hurry up."

Simon has a suite of offices in the Brill Building, the legendary working address of the hit songwriting teams in the pre-Beatles days, like Gerry Goffin and Carole King. Near the receptionist's desk in the front room is a round glass case filled with Grammys. A dozen or so platinum records, each representing sales of 1 million albums, are tacked up on an adjacent wall.

Simon's office, which is behind some double doors, feels like a living room decorated by a frequent flier. There's a deep sofa, a couple of comfy chairs, and walls lined with souvenirs: a signed photo of Joe DiMaggio, trinkets from Africa and South America, a shot of the railway station in England where he wrote "Homeward Bound." In one corner is a piano, in another the stand-up bass that belonged to his father, now deceased, who was a professional musician.

"My dad thought it was a good field to get yourself through college," Simon says, recalling his father's attempts to dissuade him from a musical career. "But what I was heading out to be was really more than a musician, because I was writing. I was training to be a recording artist, and that's another career."

Simon is shy and guarded. He politely deflects questions about his third wife, Edie Brickell, who had a singing career in the '80s and '90s, as well as questions about their three young kids and how he spends a typical day. He is slight and his speaking voice is thin, making him seem both fragile and weighted down. He speaks in paragraphs that unspool in something close to slow motion. When the subject of songwriting comes up, he slows down even further.

"A lot of it is just gathered thoughts or phrases that coalesce into something, and some of it is just the sound of the words with the melodies," he says. "A lot of it doesn't make any sense for a long time and then starts to make sense, and the ones that do make sense I refine."

Simon is an inveterate polisher and retooler, known for honing new songs for weeks or months before recording them. But his great creative jumps have taken him a little by surprise, he says, as though they arrived in a brown package from another Zip code.

" 'Bridge Over Troubled Water.' Where'd that come from?" Simon wondered in a way that suggested he didn't have a clue. "There was a qualitative leap when I wrote 'Bridge.' I thought it was better, the same way I thought 'Sounds of Silence' was better."

"When I wrote, 'Where have you gone, Joe DiMaggio,' " he continued, reciting the line from "Mrs. Robinson," "I wondered, 'What does that have to do with 'The Graduate'?" -- the 1967 film for which Simon and Garfunkel provided one of the great movie soundtracks -- " 'Can I say that? I'll just say it. It sounds right.' "

Much of the raw material comes from phrases that he stumbles into. "Mother and Child Reunion," for instance, sprang not from anything heartwarmingly familial; it was the name of a dish in a Chinese restaurant that included both chicken and egg.

"Me and Julio Down by the Schoolyard" was inspired by a playground that he used to pass by. Thinking about it one day, Simon started to sing the words "Me and Julio," and for some reason, it just tickled him.

"That was 30 years ago," he recalls, "and Julio was not a name you'd hear in a popular song. It might have been a name you knew about in East Los Angeles or New York, but not anywhere else. It was unusual to give a character that name." Simon kept strumming and kept grinning.

Eventually, his tickle became a Top 40 hit.

Simon was born in Newark and raised in Queens along with his younger brother, Eddie. As a kid he listened to his dad's band and the Latin group that alternated with it at Roseland, as well as endless hours of New York radio in the mid- and late '50s. The germination of all his stylistic crossbreeding, he says, started then.

"I have a perfect aural memory. It turns out that I remember sounds in more striking detail than I would have thought given the amount of attention that I thought I was paying."

Years after the fact, he vividly recalled the pleasure of hearing a tenor sax and a baritone sax played together. "I heard it on a record called 'Eddie My Love.' It was an early sound that went away. Many of those sounds went away, like acoustic piano and vibraphone. They disappeared, but they were good sounds, and at a certain point I became more curious about sounds and why they mixed."

He met Art Garfunkel in grade school and, with the Everly Brothers on their minds, the two formed Tom & Jerry and recorded a teen trifle called "Hey, School Girl." It rose to No. 49 on the Cash Box charts and landed the two on "American Bandstand." Simon was 16 years old. But follow-ups flopped, and Simon headed to Queens College, where he majored in English and then had an academically disappointing, and brief, experience at law school.

He and Garfunkel crossed paths again and eventually recorded an album called "Wednesday Morning 3 A.M.," released in 1964, which sold miserably.

So Simon flew to England, where he performed throughout the country. He recalls it as one of the happiest periods of his life.

"There was a good place for me, and I had great friends. I was living a kind of youth life, a no-responsibility youth life, and playing music probably four or five nights a week. It was a very free period, the last period of my life when I was not famous."

Unbeknown to Simon, a producer took "The Sound of Silence," an acoustic cut from "Wednesday," and added a rhythm section. It caught on, and by 1966, Simon and Garfunkel were the literate New York voice of the '60s folk-rock boom. Four studio albums as a duo would follow.

"That was a great period, too," he says. "Except towards the end."

When Simon went solo there were skeptics, including super-producer Clive Davis, who is usually clairvoyant on these matters but who firmly told Simon he would fail on his own. He didn't. His self-titled debut, released in '72, won raves and was a modest commercial success. The follow-up, "There Goes Rhymin' Simon," fared even better. By then, Paul Simon's credibility as a solo artist was no longer in doubt.

Not until the soundtrack to "One Trick Pony," a 1980 movie he wrote and starred in, did Simon stumble. By 1986, when he began to make "Graceland," a collaboration with the South African a cappella group Ladysmith Black Mambazo, he had, as he puts it, fallen out of fashion. Which, artistically speaking, helped.

"I didn't think 'Graceland' was particularly risky, because I don't think I had a whole lot to risk. The album before it was 'Hearts and Bones,' and it was my least successful album in terms of sales. . . . I was already out. Given the fact that nobody was paying any attention and nobody was looking over my shoulder and asking to listen to a couple tracks, it allowed for a certain freedom that was very beneficial to the record."

It's a freedom, for better or worse, he feels now. There was the "Capeman" disaster, and though Simon is proud of his last album, "You're the One," it yielded little feedback, something he still craves. What the Rolling Stones are doing now -- selling out stadiums by reliving the "Jumpin' Jack Flash" years -- holds no appeal, he says. "Creatively," he says in a tone that apologizes for such bluntness, "they're dead."

"My writing still has a purpose and a meaning. It's very hard to keep a perspective about it. I don't really know if I'm going to succeed, and I don't know how you measure that success. Success can be measured in so many ways."

After a Muse-less spell, inspiration is returning in what he calls a trickle, and he's spending long hours trying to coax more magic from his guitar, playing scales and arpeggios so repetitiously that he says it would drive any listener mad. Four songs have been written, and he thinks a theme will emerge eventually. It's a start. If Simon's innermost wish is granted, the fruits of this struggle will echo someday on a street corner near you.

The creator of a canon that places him among the great American songwriters of the 20th century: Simon, reunited with Art Garfunkel in 1975 and at the Montreux Jazz Festival, right, last summer.Paul Simon with Joseph Tshabalala, left, and other members of Ladysmith Black Mambazo, one of the South African groups he championed in the mid-1980s."My writing still has a purpose and a meaning," says Paul Simon.