Librarians in central London got a surprise delivery last week as a book turned up in the post - 40 years late.
The book had been due back on 8 August 1966
The book, Joseph Conrad's Nostromo, sent anonymously from an address in Kent, had been due back at Little Portland Library on 8 August 1966.
But it never made it back - the library closed 20 years ago and it was staff at Paddington Library, in Westminster, who received the book.
However it was too old to put back as library stock and had been sold off.
It was borrowed in the days before membership cards and barcodes, and when it was sent back it still had the blue plastic token carried by readers fitted inside the front cover.
Westminster councillor Daniel Astaire said: "We were extremely surprised to have this book returned after such a long time.
"The only reason that we can think of this book being returned now is that the original borrower was moving house or perhaps had even deceased, with someone coming across this book in the process of sorting out their possessions."
Westminster Council fines 15p a day, not including Sundays, for late books, which would have potentially brought the fine for Nostromo to £1,802.
But the reader need not have worried - the council caps the maximum fine at £5.
In 2001, former London student Mohamed Bokreta returned a book to South Thames College, 24 years after he borrowed it.
The book - Peasant Wars of the Twentieth Century, by Eric R Wolf - had been long assumed lost after it was taken out in 1977.
It was sent back in the post from Algeria with a letter seeking forgiveness from the college principal and library staff.