A former student at an Arizona school has returned two library books, 50 years late, and with a $1,000 (£600) cheque to cover overdue fees.
Librarian Georgette Bordine at Camelback High School in Phoenix said the books were checked out in 1959.
The person, who wanted to remain anonymous, calculated the fee as 4c a day, with some extra in case the rates had changed, media reports said.
Apparently the books were inadvertently packed when the student moved state.
Ms Bordine said the money would be used to buy more books, with the overdue ones – about conservation – returned to the shelves.