His fifth-grade music teacher advised him to switch to tuba lessons because he had "absolutely no talent" for guitar. But this year Barry Louis Polisar -- with his guitar -- is celebrating his first decade as a professional composer and performer of children's songs. At age 30 he has seven albums and an impressive list of radio, television and concert appearances to his credit. And this fall "Noises From Under the Rug," a lavishly illustrated song book with lyrics from more than 100 Polisar compositions, will be published.

So much for music teachers.

What that early critic could not foresee was that Polisar would grow up to challenge the traditional concept of songs for kids. "I never liked what was generally known as 'children's music' -- flowery, sweet songs of love and trees and smiling, happy families," he says. "I knew someone had to be a barometer for reality."

So, following the lead of such artists as Danny Kaye and Loudon Wainwright III, Polisar has created humorous but honest songs dealing with the Basic Truths of childhood: etiquette ("Don't Put Your Finger Up Your Nose"), nutrition ("They Said, 'Eat the Broccoli' "), sibling rivalry ("Never Cook Your Sister in a Frying Pan"), metaphysics ("Mom said, 'No'; I said, 'Why?' "), child psychology ("I'm Standing Naked on the Kitchen Table Trying to Get Your Attention ") and schoolyard bullies ("Stanley Stole My Shoelace and Rubbed It in His Armpit").

He occasionally has to contend with protests concerning his work. Most of his albums are bought by libraries and public schools, but, he says, "in the beginning, several library systems refused to carry my records because they said I 'undermined traditional authority.' " Some local county facilities still will not carry Polisar's materials, and "every once in awhile I get letters from people who think I'm giving kids 'bad ideas.' "

But Polisar maintains that his songs do not advocate revolution or sibling abuse. Rather, they play on and exaggerate thoughts children already have, to "defuse" them, a distinction he believes his young listeners understand. Indeed, his concert audiences seem to accept the various levels of his music -- even parents sing along.

Born in Brooklyn, Polisar moved to the Washington area when he was 7. He has two brothers and a sister, all younger, and admits that his songs are "more autobiographical than most people would imagine."

"With a little sister who ran away to join a carnival, an uncle who lived in a tent and a mother with 27 cats, I figured I knew all about normal family life," he explains.

Despite the fifth-grade trauma, he continued to want to play the guitar, so at 19 he invested in the same $40 nylon-stringed instrument he still uses and taught himself to play. Soon thereafter a public school teacher who had heard he wrote children's songs asked him to perform for her class. The kids loved it, and so did Polisar. Word of mouth got him six months of bookings, "and it's been like that ever since."

By the time he was 20 Polisar had released his first album, " 'I Eat Kids' and Other Songs for Rebellious Children," on his own label, Rainbow Morning Music. "I just went ahead and made it myself," he says, "even though I knew nothing about the industry, because the alternative was spending three or four years trying to convince a record company to do it."

The song ideas kept coming. "Being a writer is really being an observer," Polisar says, "being open to the world around you. I try to look at life and see its ironies, and write about them." Events he witnessed on the school concert circuit inspired such classics as "I Got a Teacher, She's So Mean," "Shut Up in the Library" and "I Don't Believe You're Going to the Bathroom." Realizing "I can write songs about anything," he even tackled the intimate topic of "Underwear."

In 1978, after putting himself through the University of Maryland (where he majored in literature and film), Polisar began performing full time. Over the years his concert bookings have mushroomed, and the record orders have climbed from two to 200 per week. He now produces a line of cassettes, has hired an accountant and just purchased a personal computer.

On getting older, Polisar says, "I used to say all my groupies were under 12. But lately I've been interviewed by several college students who said they used to listen to my records when they were kids." He and his wife Roni plan to have their own child in the next few years. Polisar adds, "I feel I have one of the few occupations which would allow us to have children and write them off our taxes as research."