A library in Minnesota recently received a returned book that was overdue by quite a few years — 47 years, to be exact.

Karen Rodricks, senior library services supervisor at the Washington County-based Lake Elmo Library in Minnesota, didn't think the package she found on a library service desk on Wednesday, Nov. 2, was going to be anything out of the ordinary.

But Rodricks said that when she saw that the parcel had no return address, she decided to gather the rest of her team before seeing what was inside.

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"‘Well, this is interesting … I’ve got a package here, and I wonder what it’s from,'" Rodricks said she told her team.

"I wasn’t concerned about it or anything — and I opened it and inside was this really carefully wrapped auto repair book," she told Fox News Digital. 

Inside the mysterious package was a copy of "Chilton's Foreign Car Repair Manual" neatly enclosed in bubble wrap.

Rodricks said that when she opened the book, she found an envelope filled with a "cute, thoughtful" handwritten note from the anonymous sender, she said.

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"In the mid-1970s," the note read, "I was living in Lake Elmo and was working on an old Mercedes Benz. I took out this book for reference. A few months later I moved and apparently the book got packed up. Forty-seven years later, I found it in a trunk with other interesting things from the '70s."

The note continued, "It’s a little overdue, but I thought you might want it back. My apologies to anyone in Lake Elmo who was working on an old Benz in the last 47 years."

Rodricks looked back inside and found what she believed, at first, to be a crisp $100 bill. 

"My dad always said if you have crisp notes, rub ‘em — and there was another one. There were two $100 bills," Rodricks said.

While the money was a very kind gesture, that's not what stood out most to Rodricks, she said.

"The best thing about this whole experience was in [the person's] note and in his care to return it," Rodricks explained.

"Even though it was 47 years late, he’s showing he really appreciated the library back in the '70s and he still appreciates the library now … This is one of the nicest thank-you notes you can send somebody."

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"The cake was the note," she added.

The library did have to recycle the book due to some oil stains on the binding.

Rodricks said she saw this as a great opportunity to emphasize that Washington County Library "doesn’t charge overdue fees anymore."

"In early January 2022, we stopped charging a flat overdue rate. The only thing we would charge for is if the book doesn’t get returned. It doesn’t matter how long [ago] it is," she said.

This effort by the library is rooted in its desire "to make the library more accessible and remove some barriers," according to Rodricks.

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Rodricks noted that the $200 from the anonymous sender will be sent to the Washington County Library headquarters.

It will be placed in a pool that may be used by the different branches, including Lake Elmo Library.

Rodricks has been working in Washington County libraries for 10 years and has overseen the Lake Elmo branch for two years.

"The receipt of this letter and this package confirms all my positive viewpoints of the library and working there," she said.