A first edition Harry Potter book which a father used to teach his children English has fetched £60,000 at auction.
The rare copy of Harry Potter and the Philosopher's Stone had been valued at £30,000.
The book, one of only 500 hardback first editions printed, was sold by a retired British expat from Luxembourg.
Auctioneer Jim Spencer described the hammer price, which climbed to £75,000 with the buyer's premium added on, as "astonishing".
The novel went under the hammer at Hansons' Staffordshire Library Auction on Tuesday.
The vendor, who wanted to remain anonymous, said he had bought the book for his children about 18 months after it was first published in June 1997.
He said he was "absolutely delighted" with the sale.
"The Harry Potter books are truly iconic - in the very top tier of literature for children - and this first edition can only increase in value in the future," he said.
The seller added he planned to use money from the sale to pay off his daughter's student loans.
The book was identified as a first edition, after being posted to the Derbyshire auctioneers in a tea towel, as it has a duplication of phrase '1 wand' on page 53 and an issue number of "10 9 8 7 6 5 4 3 2 1".
Hansons' said the final bid came from a private international buyer who was bidding by phone.
Mr Spencer, who has dealt with the sale of four first editions of Harry Potter and the Philosopher's Stone, said it was the highest price paid at the auctioneers for a copy.
"I'm absolutely thrilled the book achieved such an outstanding price for our vendor," he said.
"I hoped it would make £50,000 but to see it sail past that to reach £60,000 was astonishing."