I used to scoff at the idea of preschool “graduation.”

In my day, no such thing existed. In fact, if you even attended preschool, or playschool as it was usually called, you were summarily dismissed once you turned 5, and then packed off to kindergarten where your indoctrination into the rigidity of societal structures was swiftly initiated.

I often told my millennial college students that their trophies for participation and their silly ceremonies were not for me, a crusty old Generation Xer.

Then, this very morning, I found myself seated in the sanctuary of St. Catherine of Siena watching my youngest son, in his blue cap and gown, receive his preschool diploma.

I couldn’t help it; I cried. As he processed out of the church, he left behind not only a wonderful chapter in our family’s lives, but also a precious piece of his own childhood. He leaves ready for kindergarten, yet though he is only 5 years old, he also leaves behind a small bit of innocence.

Very few artists have been able to capture sincerely, and without sentimentality, the mystery and magic of childhood. Even fewer have been able to approach the experience of childhood with an appreciation for the innate wisdom that children possess. The great British writers of children’s literature have been able to do it, and the marvelous artists of the 20th-century American picture book have also succeeded. Yet in a medium aimed not only at children, but at a universal audience of all ages, only a few have accomplished the feat of rendering children as not only wonderful, but real.

In my mind, nobody has done it better than Charles Schulz, the creator of the most beloved comic strip of all time, “Peanuts.”

Charles Schulz was a true genius, maybe one of the most important geniuses of modern America. Working almost completely alone, he created a cast of characters and a world that day after day, every week and every year, for decades captured the hearts and the minds of people all over the world.

Say Charlie Brown, or Linus, or Lucy, or Snoopy to anyone, and immediately they smile. Those characters evoke what Schulz famously called simply, “happiness.”

When you mention “Peanuts” to people of my generation, without fail they recall not so much the newspaper strip, but the marvelous seasonal television specials that for many people were as essential to the calendar as the lunar cycle or the liturgy. What’s Halloween without the Great Pumpkin? And what would we do at Christmas time without the “Peanuts” Christmas special, and Linus’ wonderful, unapologetic recitation of the nativity story, taken verbatim from the Gospel?

While many of us know those specials, and others like them, by heart, they would not be the same without the crucial ingredient that makes them different from other animated programs. That essential piece is music, and for “Peanuts” the music is integral, even inseparable, from the narrative and the visual elements of the shows.

The music of “Peanuts” is jazz, as uniquely American as Charlie Brown’s love of baseball and Lucy’s twist on the lemonade stand. And the jazz of “Peanuts” is the creation of a brilliant Catholic composer and musician named Vince Guaraldi.

Guaraldi was born in 1928 in the bohemian North Beach section of San Francisco. He grew up in the Bay Area, graduated from high school, and following two years of military service, returned to San Francisco to attend college. In the early 1950s, when jazz was booming all over the country, Guaraldi began to devote more time to music than to school. He played in nightclubs, including the famous Blackhawk in San Francisco, where he once sat in for the famous pianist Art Tatum. He began recording with Cal Tjader, and became part of Tjader’s performing band. As the decade went on, Guaraldi’s reputation grew and he took jobs as both a session musician and a teacher. In the late ’50s, he was touring with Woody Herman’s famous big band.

A track on a 1962 LP, a song titled “Cast Your Fate to the Wind,” became a sensation for Guaraldi. The record inspired a documentary film, “Anatomy of a Hit,” and became a gold record, eventually winning a 1963 Grammy award for Best Instrumental Jazz Composition. Guaraldi was now an established musician in his own right, a respected and legitimate front man for a trio that made many successful records.

Nicknamed “Dr. Funk” by his peers, Guaraldi had an instantly recognizable unique sound. His music was modern, yet accessible, and he seamlessly blended Latin influences such as samba and bossa nova into the familiar classic setting of a jazz piano trio.

Guaraldi was always open to experimentation, particularly when his music could be shared with audiences or circumstances not necessarily associated with jazz. One of Guaraldi’s proudest achievements was the composition and performance of a choral Eucharist set to jazz. Guaraldi’s jazz Mass was performed at San Francisco’s Episcopal Grace Cathedral, and was released on record. As Guaraldi wrote, “I had one of America’s largest cathedrals as a setting, a top choir, and a critical audience that would be more than justified in finding fault. I was in a musical world that had lived with the Eucharist for 600 years and I had to improve and/or update it to 20th century musical standards. This was the most awesome and challenging thing I had ever attempted.”

In keeping with his willingness to try new things, Guaraldi eagerly accepted the offer to write the music for a 1964 television documentary on the “Peanuts” phenomenon; he was an avid follower of the strip. Producer Lee Mendelson had heard “Cast Your Fate to the Wind” on the radio, and contacted Guaraldi. The documentary film was made, but sadly never aired; nobody believed there was an audience for a film about a comic strip, let alone one accompanied by an odd jazz soundtrack. Soon after their initial meeting, Guaraldi had played a new song for Mendelson over the telephone. The song was the famous “Linus and Lucy,” the irresistible fast number that was finally heard on “A Charlie Brown Christmas” in 1965, and which remains perhaps Guaraldi’s most famous tune.

It is estimated that roughly half of America watched “A Charlie Brown Christmas” when it debuted, and the show’s music became a sensation. Schulz recalled that the music “captured something about the lilting quality of the kids—the way they walk along and bounce a little bit.” More importantly, Schulz had the humility to acknowledge that in fact “the music came to mean the characters.”

In the recently issued 50th-anniversary LP of “A Boy Named Charlie Brown,” famous producer and critic Ralph Gleason’s original liner notes are included. Gleason praises Guaraldi’s great achievement as “he took his inspiration from the creations of Charles Schulz and made music that reflects that inspiration, is empathetic with the image, and is still solidly and unmistakably Vince Guaraldi.”

The great beauty of jazz is that the music requires the performer to improvise. The musician may be playing a song not of his own making, yet if his performance is good, he makes for a moment the song his own. He participates in something that is greater than himself, and in doing so, he is able to more fully appreciate his own individuality in relation to the larger whole. Is it any surprise Guaraldi was able to compose music inspired by and for a Eucharistic liturgy?

In a great and tragic irony, the last song Guaraldi ever performed was a rendition of the Beatles’ “Eleanor Rigby,” one of the most powerful two-minute social commentaries ever made. And like Eleanor, who “died in the Church and was buried along with her name,” Guaraldi collapsed and died during a break after the set. He was 43 years old.

“Nobody came” to Eleanor Rigby’s funeral, and “no one was saved” after Father McKenzie’s eulogy for her, but come they did to Guaraldi’s funeral Mass at Our Lady of Mercy Catholic Church in Daly City, California. Guaraldi’s “Peanuts” music was played in the church before his burial at Holy Cross Cemetery.

Guaraldi once said that his great ambition was “to have people like me, to play pretty tunes and reach the audience. And I hope some of those tunes will become standards. I want to write standards, not just hits.”

There is no doubt that Vince Guaraldi accomplished his dream. His music remains widely available on record, and of course we hear it every year at Christmas. It is music written not just for children, and not just for characters who embody the essence of children. It is music for all the people that the “Peanuts” are, and all that we are: the irrepressible and imaginative, the foolish and the wise, the winners and losers, the lovable and unlovable.

And that’s what being Catholic is all about, Charlie Brown.