They could have thrown the book at him.

A former patron of the library in Lake Elmo, Minnesota, has returned a car repair manual – 47 years late.

The borrower included an apologetic note along with the book — Chilton’s Foreign Car Repair Manual: German, Swedish, Italian Cars, Vol. 1 — which was checked out in 1975.

“It’s a little overdue, but I thought you might want it back,” the writer said in the unsigned missive. “My apologies to anyone in Lake Elmo who was working on an old Benz in the last 47 years.”

The unidentified person also explained why they held onto the book for nearly half a century.

“In the mid-1970s, I was living in Lake Elmo and I was working on an old Mercedes-Benz. I took this book out for reference,” the person writes.

“A few months later, I moved and apparently the book got packed up. Forty-seven years later I found it in the trunk with other interesting things from the 70s.”

The Washington County Library System shared the tale of tardiness on Facebook, explaining that it was happy to get the book back, and revealing the good news for the borrower that there won’t be any late fees.

“The writer was also concerned about any overdue fees, but since we don’t charge those, it’s no problem,” the library said, according to UPI.

A Facebook user asked when the library stopped charging fees for overdue books.

“Good question! We haven’t had daily fines for overdue materials for a long time, but we do still charge a replacement fee if an item is lost or damaged,” the Library System replied.

“Back in January we also eliminated what was called a ‘processing fee’ related to extremely overdue items, so now there are no charges for materials that are returned late, just those that are lost or damaged,” it added.