Larissa Picard has probably read “Lost on a Mountain in Maine” 15 times.

She was in grammar school when she first read the true story of Donn Fendler, a 12-year-old boy who survived nine days alone on Mount Katahdin in 1939. But she kept reading it and, in her 20s, felt compelled to write to Fendler to tell him how much the book meant to her, how she often read it “to remind myself of what is important in life.”

“He’s alone. He has to confront his fears and the many obstacles that are trying to prevent him from getting home again, but he keeps putting one foot in front of the other and using the skills and knowledge he’s learned to that point to make smart decisions,” said Picard, 54, who lives in Topsham and is executive director of the Pejepscot History Center in Brunswick. “He overcomes all the monsters and he makes it back.”

Larissa Picard, of Topsham, read “Lost on a Mountain in Maine” as a child and wrote to Donn Fendler as an adult. Shawn Patrick Ouellette/Staff Photographer

“Lost on a Mountain in Maine” has been a must-read for generations of Mainers, thanks to all the teachers who have used it as part of the Maine Studies curriculum for fourth graders over the decades. The book’s story was also kept alive by Fendler himself, who spent the last 25 years or so of his life sharing his story at Maine schools, libraries, Scouting events and pretty much anywhere he was invited. He died in 2016, at the age of 90.

Now, Fendler’s story will have a new chance to inspire people all around the country, thanks to the film “Lost on a Mountain in Maine,” which opened in theaters nationwide Thursday. One of the film’s producers, Ryan Cook, is a Waterville native who read the book as a youngster, first with his parents before a hike of Mount Katahdin and then with his fourth grade class. He remembers being in awe when Fendler visited his class at Albert S. Hall School.

Donn Fendler chats with a young reader at a book signing in Bangor in 2011. Associated Press/Michael C. York

“To hear him telling his story was super impactful. He wasn’t just the author; he had lived through this experience,” said Cook, 38, who worked for more than a decade to get the film made. “There are kids who love Michael Jordan or Wayne Gretzky, but I love the outdoors, and Donn was my kind of hero. This is somebody who went up against something awful and real and survived.”

Fendler’s disappearance in the Maine woods in July of 1939 made national headlines. He survived nine days without food – walking 48 miles and losing 16 pounds – before he finally happened upon a hunting camp. After his ordeal, President Franklin D. Roosevelt presented Fendler with the Army & Navy Legion of Valor’s annual medal for outstanding youth hero. He was celebrated with a parade and an article in Life magazine. Later that year, Fendler told his story to writer Joseph B. Egan, for the book “Lost on a Mountain in Maine.”

Donn Fendler, 12, of Rye, N.Y., is shown with the sack that he used as a sleeping bag while he wandered for days in the wilds of Maine in 1939. A Boy Scout, he survived more than a week without food – walking 48 miles and losing 16 pounds – before he finally happened upon a hunting camp in Stacyville. Portland Press Herald graphic by Jeff Woodbury

Though the book is still in print, this is the first film adaptation of Fendler’s story. The small-budget indie film was backed by Sylvester Stallone’s Balboa Productions and shot mostly in the Catskill Mountains, because New York provides greater financial incentives to film companies than Maine does, Cook said. The film stars Luke David Blumm, who was in the recent Netlix horror series “The Watcher,” as the young Fendler. Paul Sparks, who played an ill-fated journalist in “House of Cards” on Netflix and a gangster in HBO’s “Boardwalk Empire,” is cast as Fendler’s father. The movie premiered in July at the Maine International Film Festival in Waterville.

Avery Bilodeau, a fourth grader at Saint Dominic Academy in Lewiston, read the book this fall. She and her classmates were asked by their teachers to record TV news-style reports on the book. For her report, Avery held a plastic microphone in front of a hill covered with rocks. She told her viewers that a 12-year-old boy had gone missing on Katahdin’s Saddle Trail, and that “as you see today,” conditions on the trail are rough.

But her favorite parts of the book, Avery said, dealt with Fendler’s encounters with woodland creatures and his eventual rescue.

“He had a dream about a squirrel telling him that this tote road led to camp. Then he woke up, and he saw a squirrel, so he followed the tote road, but it never led to a camp,” said Avery, 9, who lives in Lewiston. “Then he saw a bear and had a dream about that. Then he found another tote road and he was happy, because it led to a camp.”

Ryan Cook at the Waterville Opera House, where “Lost on a Mountain in Maine” premiered in July. Rich Abrahamson/Morning Sentinel

Though the book is not a required element of the Maine Studies curriculum for the state’s fourth graders, hundreds if not thousands of teachers have chosen to use it over the years. It fits well as part of Maine Studies because it’s so relatable to students that age, said John Thurlow, a retired elementary school teacher from Scarborough, who began using the book in his classes more than 30 years ago. It’s especially effective at engaging reluctant readers, Thurlow said.

“It’s written in a kid’s voice, and it’s a survival story, a cliff-hanger, so it has the elements to really engage kids that age,” said Thurlow, 63, who read the book himself as a child. “It’s just one of those books for kids that seems to have universal appeal.”

John Thurlow, a retired teacher from Scarborough, says “Lost on a Mountain in Maine” always engaged students. Shawn Patrick Ouellette/Staff Photographer

The story was especially appealing to young people in Maine, who aren’t often presented with books in school about exciting things happening to other young people in Maine.

“It’s a great kids’ adventure story, but the fact that it happened close to your own community in Maine made it so much more vivid,” said musician Griffin William Sherry, 37, who grew up in Buxton and read the book. “And, for me, it was a generational thing. My parents’ parents had read them the book, then it was my turn.”

News Center Maine anchor Amanda Hill, who grew up in Turner and often played in the woods nearby, remembers the book making her think a little more carefully about the potential dangers of being out in the wild. It also made her listen a little more closely to advice about hiking safety.

“After I read it, I remember thinking, ‘Yikes, are the woods a scary place?’ ” said Hill, 39. “I remember it being part of a larger conversation with adults about what to do if you get lost. We talked about what he did right and what he did wrong.”

News Center Maine anchor Amanda Hill grew up in Turner and remembers the book making her think more about wilderness safety. Derek Davis/Staff Photographer

Thurlow remembers Fendler coming to school visits with extra copies of his book to sign, in case a youngster didn’t own a copy. Fendler also never charged schools for his visits, Thurlow said, not even for mileage for trips that were far from his home in Newport.

“He loved sharing his story, and he loved the interaction with kids,” said author Lynn Plourde, of Winthrop, who worked with Fendler and artist Ben Bishop to create the 2011 graphic novel “Lost Trail,” based on Fendler’s story. “As he got older, it got more physically challenging for him to go to all these places. But once he got there, it was like he flipped a switch and you could see in his face how happy he was to be there.”

Hope Mills Keleher, a teacher at Lyseth Elementary School in Portland, remembers trying to get Fendler to come to her class one year, when he was living much of the year in Tennessee and only part of the year in Maine. He was such a popular speaker that all his available dates were booked, Keleher said. So instead, her students wrote Fendler with questions, and he wrote back to answer each one – about 16, Keleher remembers.

“Sometimes I run into students from years ago, and they say their favorite part of fourth grade reading was ‘Lost on a Mountain in Maine,’ ” said Keleher, 56. “And I loved teaching it.”

Hope Mills Keleher at Lyseth Elementary School in Portland. Brianna Soukup/Staff Photographer

Chuck Major, of Orono, scout executive for the Katahdin Area Council of the Boy Scouts of America, heard Fendler speak to scout groups over the years. He said once Fendler caught a boy who wasn’t paying attention and told him that if he (Fendler) had paid more attention as a Scout, he probably wouldn’t have gotten lost.

Major said many Scouts, who had done some hiking and studied wilderness preparedness, were pretty much in awe of Fendler when they met him.

“A lot of the kids were like, ‘How did he survive up there?’ ” said Major, 65. “Even as the years passed and there was more of an age gap between himself and the kids he was speaking to, (the Scouts) were always impressed.”