OGUNQUIT — For his senior thesis at Bates College in Lewiston, senior studio art major Matt Tavares wrote and illustrated a children’s picture book about a boy who caught a magic foul ball at Fenway Park.

He could not have imagined that 22 years after his graduation, he would have 20 published volumes, including his most recent— a lushly illustrated tale of how Santa got his reindeer.

“Dasher,” the new book, landed on The New York Times’ bestseller list shortly before Thanksgiving, a first for the acclaimed children’s writer and illustrator.

Tavares is “very happily surprised” about that.

The book’s roots lie in a call from his editor, who suggested he try a holiday-themed book featuring animal characters, the sort of volume that could, with a little luck, catch the public’s eye.

Tavares said he liked the concept but after mulling it all day, “I came up with nothing” beyond the possibility it could focus on reindeer.

Then as he was making the 10-minute drive between his home and his 12-year-old daughter’s basketball practice in Wells, “the whole story” came to him: a tale of a brave reindeer doe in a traveling circus, dreaming of freedom under the North Star.

Without giving much away, Dasher reaches Santa and the holiday magic triumphs, filling a major gap in the whole Santa story: just where did those flying reindeer come from?

“It feels like the story of Christmas,” Tavares said, and the words and art he produced to bring it to life have obviously resonated with others.

“It’s fun to have this happen,” he said, with “Dasher” now one of the best-selling children’s books this season.

“Gorgeous illustrations make this one sure to fly off shelves ‘like the down of a thistle,’” Kirkus Reviews pronounced.

But the one that got him started is that long-ago thesis back at Bates, which he called “a dress rehearsal of what I do now” during a recent interview in his small studio in his purple-painted home with a white picket fence just a short walk from the ocean.

Tavares, who grew up in Winchester, Massachusetts, a Boston suburb, said he’s always loved to draw.

But he wasn’t sure at age 17 that he was quite ready to commit himself to a career as an artist.

So he opted to go to Bates, a liberal arts school with a solid arts program in a new building that seemed to have smart teachers and a warm atmosphere.

“It just felt right,” Tavares said.

Tavares felt comfortable heading to Maine for college. He’d been vacationing every summer in Ogunquit for years with his parents and three sisters, he said. His parents bought a place there when he was in about fifth grade, he said.

At Bates, he said, he thought about his future, trying “to figure out how to draw every day as a grown-up.”

Paintings and galleries “never really appealed to me,” Tavares said, but the picture books he remembered from childhood did.

As he contemplated his options, thinking about some Norman Rockwell creations he loved, the notion of illustrating a children’s book began to grow on him.

“I was really drawn to that,” he said, in part because “a children’s book, it lasts forever,” or at least a lot longer than the average illustration. Its permanence mattered to him.

Tavares had long recognized that the best children’s books often contained some terrific art, from favorites such as Dr. Seuss to Bernard Waber’s “Ira Sleeps Over,” a 1972 volume he read “a million times” because he loved it so much.

Chris Van Allsburg’s “The Widow’s Broom,” a 1992 children’s book with gorgeous sepia-toned drawings, showed him what was possible artistically.

“Really into baseball,” Tavares said, he decided to create a volume that focused on the game. He said he set it at Fenway Park because it “is this pretty magical place and I wanted to capture that as a book.”

He said his professors encouraged him to try it. Tavares said his thesis adviser, Robert Feintuch, believed in letting students explore their ideas.

He hoped from the start that he could get the book published, but he didn’t know anyone who could help.

“In a way, it’s good that I knew nothing about the publishing industry and what I was up against,” Tavares said.

He found an agent, though, who was a friend of a friend and she shopped the book around, landing him a deal with Candlewick Press that has served him well ever since.

After graduation in 1997, he moved to Arlington, Massachusetts, outside Boston, where he lived for five years, working on more books, often about baseball, and meeting the woman who became his wife, Sarah, a special education teacher who grew up in Wiscasset.

He and Sarah moved into the house in Ogunquit that Tavares’ parents had bought years earlier, renting it at first and then buying it for themselves as they raised two children there.

Looking around his studio, with shelves full of children’s books and graphic novels, Tavares said he can remember sitting in the room as a child, coloring with crayons.

He’s come a long way, learning all sorts of techniques, including how to draw on a computer, to create stunning art.

Tavares, for instance, illustrated a book about Benjamin Franklin’s boyhood that’s due out in March. He just got the final proofs that show exactly what it will look like.

At one point, he said, an editor thought the Boston docks in one picture looked “too dusty,” the sort of thing that would be tough to change on paper or canvas.

On the computer, though, Tavares said he simply removed the third of three layers of dust from the illustration, instantly making it less dusty.

He could also move ships or people around, getting everything just so.

For Tavares, the ability to keep learning new ways to create his art is part of the craft.

“It’s fun to mix it up between the different kinds of books,” he said.

It’s not a lonely endeavor either.

Tavares said he talks often with others in his field. They even have a Skype group where they regularly offer tips and share their work.

“It’s cool to see what other people are working on,” Tavares said. “A good number of us are in Maine.”

Looking around at shelves and cabinets full of his work, his table mostly clear with just a few pencil drawings at the edge, he said it’s a good life.

“This is my favorite part,” Tavares said, “getting to sit here in my studio and draw.”

“This is really important to me. This is what I want to do,” he said. “Kids are a great audience.”