‘90s FAMILY : Every Picture Tells Her Tale : Author-illustrator Jan Brett thinks children’s stories should ring with optimism--and ancient legends are a good place to start.

Outdoors one summer day at Tanglewood, the off-season home of the Boston Symphony Orchestra, Jan Brett began fixating on the double bass her husband, Joe Hearne, was playing.

Brett, Hearne and his double bass had been cohabiting happily for years. But it was only at that moment that Brett realized, “Something could fit right inside.” She studied the carved “F” holes on the front of the tall stringed instrument.

“It would have to be a small something,” she decided. A mouse? A caterpillar? Music does that, Brett reflected. “It leads one’s thoughts to interesting places.”

Her thoughts led her to create “Berlioz the Bear,” the children’s story about a band of ursine musicians in a quaint Bavarian village that was published in 1991.

As a testimony to the humor that binds Brett and Hearne, the artist freely admits she “took off Joe’s glasses and mustache,” lengthened his nose, and used him as the model for Berlioz. As a mark of the respect Hearne has for his wife’s work, he was thrilled to be immortalized--albeit as a bear.

It is one of dozens of exquisitely illustrated titles Brett has produced, many of which have appeared on “best children’s books” roundups. In 1990, “The Wild Christmas Reindeer” even enjoyed a sojourn on The New York Times’ hardcover fiction bestseller list--normally an adults-only distinction.

The pair met 15 years ago when Brett signed up for flying lessons and Hearne turned out to be her instructor. Divorced and raising her daughter, Lia, on her own, Brett was on the verge of mega-success as an author and illustrator of books for young people.

Brett, 44, finds her professional trajectory unsurprising. A shy child, she had trouble verbalizing her feelings. “But put a piece of paper in front of me, and everything came right out,” she recalled. By kindergarten, she was determined to be an illustrator. As a student at the Boston Museum School, Brett haunted the city’s venerable Museum of Fine Arts.

She also steeped herself in fables--the timeless tales from around the world that remain her preferred vehicle of storytelling. Leave divorce, death and dysfunction to others, Brett reasons. Her imagination functions best “set back in time,” and in a place where optimism reigns. For the thousands of young readers who write to her each year, Brett has found, her message of hope serves as a channel of self-discovery.

Borrowing from ancient legends and traditions, Brett scrupulously researches her stories. To ensure accurate adaptation of the tale that became “The Mitten,” for instance, she hired a Ukrainian woman to translate the eight versions of the legend that turned up at the Harvard University library. For additional verisimilitude, Brett visited a Ukrainian neighborhood in New York City, memorizing the tiny details that win plaudits in her books.

“Feather-by-feather” precision is how critic Phyllis Theroux praised Brett for her remarkable border drawings and thoroughly believable central stories.

Why children’s books? Brett, with her mop of blond hair and her clear-eyed view of the planet, paused not one second. “It’s just that that’s the way my art looks,” she explained.

Brett and Hearne journey the globe relentlessly. In turn, both translate the teachings of their travels into their work. A forthcoming Brett book about an armadillo and a girl named Harmony Jane, as one example, was inspired by a Boston Symphony Orchestra trip to Texas.

Here in this Colonial village not far from Plymouth Rock, they share their home with Perky Pumpkin, a Siberian husky who frequently appears in her books. Life is calm, manageable--and for the most part, exactly as Brett imagined.

“Everything that has happened is what I expected,” said Brett, living proof, apparently, that wishing can make it so. There was just a breath of hesitation. “Except that I always thought I would win all kinds of awards, and not make very much money.” Brett, with a gigantic smile, laughed. “It turned out the other way around.”