It was a beach day, by Maine standards — slightly overcast and moderately balmy, with a hint of balsam in the air. But on a summer morning in July, 225 people steered clear of state parks and went to Curtis Memorial Library in Brunswick instead.

They were young and old, in strollers and on walkers and strutting the latest technical sandals. They wore pigtails, baby slings, ironic T-shirts, a headscarf, a lobster hat, a crown, a tiara and halos of white hair. Many carried colorful hardcovers and paperbacks that appeared to have served multiple generations of readers.

The crowd wasn’t at Curtis to meet a celebrity memoirist or bestselling novelist. They were there for a children’s book event: Sarah McCloskey, the real-life inspiration for “Blueberries for Sal” (1948), was at the library to read a handful of classics by her father, Robert, who also wrote “Make Way for Ducklings” (1941) and “One Morning in Maine” (1952), among others. The event was one of several celebratory occasions planned around “The Art of Wonder,” an exhibit of 68 original illustrations by the two-time Caldecott Award-winning author, which will be on display until Oct. 15.

As “Sal” McCloskey, now 78, settled into an armchair, a hush fell over the undulating sea of children at her feet. It was as if an adult version of Matilda, Pippi or Eloise had just strolled into the room in a yellow T-shirt and khakis. McCloskey’s hair is salt and pepper — gone is the tousled mop her father drew with India ink — but she still felt familiar, like an old friend you haven’t seen since preschool. This sense of abiding affection was a powerful reminder that certain characters imprint on our DNA — and that the writers and artists who conjure them have a bit of magic in their fingertips.

At the beginning of her introductory remarks, Joyce Fehl, the library’s development and marketing manager, asked the crowd, “Who has goose bumps?”

Taking in the packed room, where every chair was full, as were many laps, McCloskey answered, “I have tears.”

Then she picked up “Time of Wonder” (1957) and started to read.

In the pecking order of picture books, Robert McCloskey’s have been at the top of the heap for almost 80 years. They celebrate little milestones — loose teeth, outings that lead to unexpected adventure — and the abundant beauty of New England. Without moralizing or finger wagging, they also highlight the hard work of parents, fishermen and nature.

Children love McCloskey’s stories because they’re long — the better to prolong lights-out — and minutely illustrated down to the finest blade of grass. A drawing of a seal includes whiskers and eyebrows. Circles on a watercolor Parcheesi board are shaded just so. Even if you’ve never harvested fruit or given a hoot about ornithology, you can hear the “kuplink, kuplank, kuplunk” of berries hitting the bottom of a tin pail or the plaintive cry of a loon: “Luh-hoo-hoo-hoohoo-hoooh.”

“There is such broad appeal to these books,” said Liz Doucett, the library’s executive director. “ ‘Make Way for Ducklings’ is about finding a safe home. ‘Blueberries for Sal’ is about going out and adventuring with your mom. They’re books that resonate — it doesn’t matter how old you are.”

Planning for “The Art of Wonder” was underway before the pandemic; when Doucett and her team picked it up again, they hoped McCloskey’s art would lure readers back to the building. In the first month of the exhibit, the library hosted more than 25,000 guests (up 22% from July 2019), including visitors from 45 states, 11 countries and five continents. The number of residents signing up for new library cards reached 281, almost double the number from July 2022. Judging from an informal show of hands, one-third of the people gathered for Sal McCloskey’s visit were first-time guests at Curtis.

“We had a woman who had not been in the library since she was a kid,” Doucett said. “She loved it so much, she got a library card, and then she went and got her mother, and her mother got a library card.”

Sprawling elegantly over two floors, the exhibit contains sketches, drawings, watercolors and brush and ink images from five picture books, including Robert McCloskey’s lesser- known, slightly psychedelic final one, “Burt Dow, Deep- Water Man” (1963). A local teenager described it as the author’s “Lucy in the Sky With Diamonds.”

“This is impeccable brushwork,” said Scott Nash, executive director of the Illustration Institute, which framed and curated the show. “Bob has a confidence to his line that is rarely seen these days.”

The world McCloskey wrote about has changed drastically. Scott Island now has Wi-Fi, although his daughter still relies on a radio for information. (Sal McCloskey spends three seasons on the island and returns to Ellsworth, Maine, for the winter.)

Even the way people speak has changed, she said. “The speech was different in every little enclave of Maine. There were dialects.” And then there are environmental catastrophes: “With the warming of the waters, we’ve lost the fish,” she said. “I have watched the shore change in terms of which little beings inhabit it now as opposed to back when.”

Strolling through “The Art of Wonder” after McCloskey’s event, it was impossible not to feel hopeful about the state of the world. A pair of bespectacled children peered at duckling sketches with the gravity of historians. A retired kindergarten teacher recalled reading Robert McCloskey’s books to three decades of students.

On the second floor, framed drawings of Sal McCloskey and her mother hung on a wall near Curtis’ library of things, which includes a pickleball set, a food processor, a scanner — and, yes, a blueberry rake.

“Take a farewell look at the waves and the sky,” Robert McCloskey wrote in “Time of Wonder,” which chronicles a summer in Maine and ends with the arrival of fall. “Take a farewell sniff of the salty sea. A little bit sad about the place you are leaving, a little bit glad about the place you are going.”