Arlington’s Wakefield High School library started the school year with a surprise: an overdue book, checked out 34 years ago; returned to the library with a friendly, anonymous note.

Librarian Gina Glassman said it was the longest overdue book she had ever seen returned. Glassman said she hoped the former high schooler who sent it back after so long would come forward to reveal his or her identity. She even said the borrower wouldn’t have to pay a late fee.

Well, the mystery is solved: The tardy borrower is Eleanor Reed, who contacted The Post to reveal her identity after reading about the library’s appreciation for getting the book back after all those years.

And it turns out the story of the tardy book, and how it got back home, is perhaps an even better tale than the one within its now-yellowed pages.

Reed was a freshman or a sophomore when she checked the book out, she said. She remembers reading other novels like it: “It’s from what I always have considered in my mind the ‘cautionary tale’ section of the library. There were a lot of books that were, ‘Don’t fall in love with the wrong guy.’ ‘Don’t get pregnant.'”

At the end of her sophomore year at Wakefield, Reed and her family moved to Germany, the latest in a long string of placements for her father, who was in the Army. The library book came with them.

And the book stayed with Reed’s parents, in a box full of books, on their next several moves. “This book has gotten around,” Reed said.

Finally, it returned to Arlington when Reed’s parents moved there again. And this summer, as her parents prepared to move to a retirement home in Falls Church, Reed cleaned out the attic — and saw the library book.

Reed herself made it back to the Arlington public school system long before the book did. She has been a teacher in the school district for 21 years.

“Of all the places we lived, we sort of think of Arlington as our home town, if an Army brat has a home town,” she said. She now teaches world geography to eighth graders at H-B Woodlawn.

She said she sent the book to neighboring school Wakefield anonymously, in part to amuse the library staff. “As a teacher, when you get school mail, you go through your whole day thinking, ‘Maybe there will be something interesting in my mailbox.’ And there never is.”

She also hesitated to use her name, since she didn’t want to bring up memories of her teenage self. “Somewhere in that Wakefield library is the 1981 yearbook. And it is the most hideous picture of a teenager you’ve ever seen,” she joked. “I wouldn’t like anyone to look up to see who that was.”

As for the book itself, the one her family toted around the world for all those years? Reed agrees with the librarian’s assessment, that it’s not worth putting it back on the shelf for today’s high school readers.

“I skimmed through it again,” she said. “Looking at it now, this is a terrible story. I think my tastes have changed in 34 years.”