A rare edition of Harry Potter and the Philosophers Stone is expected to fetch more than £20,000 when it goes to auction in November at Bonhams. The book contains a small, barely noticeable typo and only 500 copies containing the error were published in 1997.

Harry Potter and the Philosopher's Stone Does your copy of Harry Potter and the Philosophers Stone contain a valuable typo?

Page 53 of the book lists the supplies Harry needs to begin his first term at Hogwarts. But what Rowling, her editors and the book’s proof reader didn't notice at the time was, the phrase '1 wand’ appears twice on the list.

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“As the first book in the series, Harry Potter and the Philosopher’s Stone has a special place in the affections of the millions of readers across the world and the proof reading error about the wand in the first edition has, of course, become a treasured piece of Harry Potter arcana,” said Matthew Haley, the head of books at Bonham’s.

“Like most enduring books aimed at younger readers, the Harry Potter books also have wide appeal to adults and there is a strong market among collectors for first editions," he added. “This copy is in excellent condition – one of the very best I’ve seen – and we’re expecting a lot of interest.”

On Friday the Harry Potter franchise debuted the covers for three upcoming tie-in books. Released on October 18th will be J.K. Rowling’s Wizarding World: Movie Magic Volume One: Extraordinary People and Fascinating Places, which will give fans a behind the scenes look at how the Harry Potter movies were made.

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October 18 will also see the release of Harry Potter: Winter at Hogwarts: A Magical Coloring Set, an interactive colouring book. Then on November 1, younger fans will be treated to J.K. Rowling’s Wizarding World: A Pop-up Gallery of Curiosities, a pop up book that also ties in with Fantastic Beasts and Where to Find Them.