| A rare first edition of Harry Potter and the Prisoner of Azkaban could sell for up to £20,000, according to internet auction firm eBay.
The people selling the book say it's definitely a first edition because of certain errors on the first few pages.
The sale price had got to £2,000 on Thursday morning, with two and half days to go, and it's rising quickly.
Publishers Bloomsbury told the BBC it was impossible to say if the book was genuine or not without seeing it.
The current owners say it's authentic because author JK Rowling's name is printed as Joanne Rowling on the back of the title page.
They also say there is a missing line of text on the first page between the words "burnt" and "so much".
Very rare
They claim it's one of only 10,000 copies like that, as the printers stopped the presses to correct the mistake.
The book is apparently unread, and has been kept in an airtight box since it was bought in 2000 for £600.
A signed first edition of Goblet of Fire sold in 2003 for £27,500.
One Potter expert told Newsround he would be surprised if the book reached £20,000.
He thought the book was probably worth closer to £2,000. | |
I'm-a thinking how much money I could make off this one...