A book borrowed from a Helsinki library was returned in May -- 84 years overdue, a librarian told AFP on Wednesday. A Finnish translation of Sir Arthur Conan Doyle's book "Refugees" was received by librarian Heini Strand on Monday at the main desk at the Helsinki Central Library Oodi. "The due date of the loan was December 26, 1939", Strand said, adding that she had never received a book so long overdue. The relationship between the person who happily returned the book and the original borrower remained unknown.