It’s a cliche: Write what you know.

But there’s a kernel of truth in every cliche. Robert Wilder writes about what he knows. And boy, does he know a lot.

The Staples High School class of 1984 graduate has spent more than two decades at Santa Fe Prep. Under the direction of fellow Stapleite Jim Leonard — the head of school — Wilder teaches English and is an assistant coach of the state champion boys soccer team. He starred in the sport at Staples, then at Wesleyan University.

With a master’s degree in writing, Wilder has built a second career as an author. His essays were published in Newsweek, Details, Salon and Parenting. He won awards and fellowships, and became an NPR “Morning Edition” commentator.

Wilder spent 10 years as a columnist for the Santa Fe Reporter. “Daddy Needs a Drink” — the best name for a column in the history of journalism — covered every aspect of parenting his two children (Poppy and London) with wit, insight and plenty of poop-filled honesty.

The column earned acclaim far beyond New Mexico, plus its share of criticism. Plenty of people called Wilder “a horrible parent.” A collection of essays formed the basis for a 2007 book by the same name. Author Augusten Burroughs (“Running With Scissors”) praised “Daddy Needs a Drink:” It “hits you in the face like a fully loaded diaper.”

The next year, in his second Random House book — “Tales from the Teacher’s Lounge” — Wilder turned his irreverent eye from his family toward his profession. He wrote about hormonal teenagers, helicopter parents and his eclectic array of colleagues. The result was — again — both humorous and dead-on

It’s not easy being a full-time teacher, part-time soccer coach and successful author. Wilder said, “I don’t waste a lot of time. Or sleep.”

Now, he haspublished his third book and first young adult novel. “Nickel” is about a teenager named Coy with a mother in rehab, an inept stepfather, and his best friend who, like Coy, is obsessed with ’80s culture. She gets sick, he gets another girlfriend, and it all comes together in a “hilarious, heartbreaking and honest portrayal of the complicated world of being a teenager today.

Burroughs (who is quite the Wilder fan) said, “No one has ever written about the pains of being a teenager — physically and psychologically inside and out — quite like Robert Wilder in his startling debut novel.”

Wilder explained how he has managed that feat. “I have a soft spot for teenagers. Luckily, I get to read their writing. I realized that they have real interior voices and lives.”

One example: A girl in one of his classes called “The Great Gatsby’s” Nick Garroway “a stage-5 clinger.”

“That’s great language,” Wilder said.

The author knows — from his career at Santa Fe Prep, and his years as a student at Long Lots Junior High and Staples — that having one good friend can help a kid get through some tough teenage years. The importance of that friend comes through powerfully in “Nickel.”

The novel took more than five years to write. He spent much of that time revising and reworking the dialogue. His first draft was written almost all in “teen code.” The final version keeps that special language, but now it’s accessible to nonteens too.

Unlike his previous books, this one is not published by a big house. Leaf Storm Press is a small Santa Fe company. They’re putting all their resources behind it, including a book tour that brings Wilder “home.”

On Dec. 1 at 7 p.m., he’ll speak about “Nickel” at the Westport Library. He’ll be introduced by Burroughs, his longtime literary supporter.

It’s a rare return to Connecticut, but Wilder looks forward to it. He recalls the influence of Greens Farms Elementary School fifth-grade teacher Barge Levy, the inspiration for one of the characters in “Nickel.”

“He was a magical man who knew how kids learn,” Wilder said. “He found kids who were hurting and made them feel good. He changed my life.” Ten years ago, Wilder was honored to be the commencement speaker at an experiential school Levy started in Idaho.

With Wilder’s broad perspective, does he think Santa Fe students in 2016 are different from those in Westport, circa his own youth in the 1970s and 1980s?

Not really. “Kids are kids,” he said. “The only difference is technology. The way they operate has changed. But I don’t take sides. As a teacher, I can’t judge better or worse. There are always new challenges and new rewards.”

One thing has changed, though. The house Wilder grew up in, off Hillandale Road, is gone.

“We have some crazy stuff in New Mexico,” he said. “But the teardown of the week in Westport is really something.”

When he sees this town and compares it to his own youth, Wilder may need a drink.

Dan Woog is a Westport writer, and his “Woog’s World” appears each Friday. He can be reached at dwoog@optonline.net. His personal blog is www.danwoog06880.com