There’s nothing like getting lost in a good book, but one reader in Finland seems to have taken that to an extreme, CNN reports.

Staff at a public library in Helsinki were rather surprised when a copy of Arthur Conan Doyle’s “The Refugees” was returned to them more than eight decades after its due date.

The novel, which is a Finnish translation of the English original, was received at Helsinki Central Library Oodi’s lobby on Monday - more than 84 years after its due date of December 26, 1939.

The returned book contained the borrower’s library card, leading staff to believe that the original patron who took out the book was a businessman from the Pursimiehenkatu area of the Finnish capital.

Librarian Heini Strand, who received the book at the library, told CNN in an email Friday: “The one who returned the book didn’t tell - and we didn’t ask - what was their relation to the one who originally loaned the book.”

Strand added: “We get these kinds of returnings that are tens of years late every once in a while, and many times they are books that friends and family find when they go through the belongings of a deceased relative. I don’t know if this was the case with this book.”

The timing of the due date could be crucial in trying to explain why the book was never returned - the Soviet Union attacked Finland on November 30, 1939.

Strand said: “The winter war had started just a month before the due date, so probably returning of a library loan wasn’t the first thing on the loaners mind at the due date.”

The copy was in reasonably good shape considering its age and may now return to circulation for public borrowing.

Strand said that the library already has two copies of the book in its collection, adding: “We sent the book to the book storage of Helsinki city library’s main library which is in Pasila.

“The people working there can decide whether to take it in to the collection or not. If it’s taken in, then library customers can reserve it online and loan the book.”

The maximum penalty for an overdue book at the Helsinki library is €6 ($6.50) but no fine is being levied as the book was no longer in the library’s system, which had changed many times since it was initially borrowed.

Siina Tiuraniemi, a librarian colleague of Strand, told CNN: “Our purpose is not to guard the books, we are here to promote reading and enable access to books and knowledge to everyone. The library is a very humane place, and people in Finland use the libraries a lot and understand how they work. Library books belong to all of us and late returns are not a big problem.”