Jon Kramer had returned to his parents’ Ontario homestead for research on a family cookbook when he stumbled upon two library books from his youth — each more than 40 years overdue.

The cooking and camping guides were checked out of Maryland’s Montgomery County Public Libraries in the early 1970s, meant to assist the family’s preparation for vacations to Minnesota’s Boundary Waters Canoe Area Wilderness (BWCA). By his count, the books had racked up a combined 85 years of late fees.

Instead of looking the other way, the Minneapolis resident decided to pay up. He made a $1,552.30 donation to cover the fees — calculated at the 1970s-era rate of a nickel a day.

A letter dated for Thanksgiving Day arrived at the county library a few weeks later, detailing Kramer’s discovery. He recounted how influential the public institution was during his childhood in Rockville, Md., and how the books had become embedded “in family lore and have acquired heirloom status.”

He offered the enclosed check, but asked to keep the books on his shelves.

“It is our hope that you will refrain from calling the FBI to report this as international trafficking or stolen goods and instead allow us the freedom of maintaining the ill-begotten literature on loan for the next 85 combined years or so, at which time we hope to make another payment to your venerable institution on their behalf,” wrote Kramer, 59.

“Sincerely in literature — the paper kind,” he signed.

The books — titled “The New Way of the Wilderness” by Calvin Rutstrum and “365 Meatless Main Dishes” by William Kaufman — still bore the antiquated Twinbrook branch library key punch cards on the inside cover.

Although it’s not uncommon for libraries to receive small donations in the mail, hearing from residents after such a long stretch of time is extremely rare, library officials said. Kramer certainly didn’t have to provide an explanation or provide a donation after all these years, said Parker Hamilton, director of the county’s public library system.

“It was a ray of sunshine for us,” she said of Kramer’s note, which she called a “love letter to libraries.” “You always want to know that you’re making a difference in peoples’ lives.”

The saga began in November after Kramer visited his deceased parents’ library at their cabin on a small island in Ontario. The 5-acre property, now owned by him and his three siblings, was purchased in 1977 with $100 down payment in coins from his sister’s piggy bank, he said.

It was a vacation home where the children spent many summers — and still do. He returned to search through his mother’s pile of cooking recipes. Among the collection of about 50 cookbooks, Kramer pulled the tattered copy of “365 Meatless Main Dishes.” A quick check of the stamped cover reminded him that it was withdrawn from the library in 1974, around the time their annual canoe trips to the BWCA began. “It was paradise to us,” he said.

When Kramer saw the cookbook, his mind immediately flashed to the camping guide, which he said was the most influential literature from their Minnesota vacations. He discovered his family had two copies, and one belonged to the library.

More than 40 years ago, the camping book planted seeds about building a lifestyle around nature and helped him appreciate the outdoors. It was something he wanted to pass on to the next generation.

A phone call to his siblings left them all in agreement; they would each chip in about $400 as a tribute to the library where they developed their love of reading.

“The library system is one of the great American institutions,” Kramer said. “It’s so formidable in many people’s education and upbringing — and [for] us even more so.”

Their donation will be used to buy new books at the Twinbook branch, some of which will likely be more modern wilderness guides, he said. On Christmas Eve, Kramer and his wife were invited on a tour of that location to thank them for their generosity.

He left with his own gift: A library card.