Harry Potter fans are being urged to sign a petition set up by a book shop chain begging author JK Rowling to write further novels in the series.
Author JK Rowling has said two characters will die in the last book
The last book, Harry Potter and the Deathly Hallows, comes out on 21 July.
But Waterstone's is hoping to gather a million signatures for its Save Harry campaign to change the author's mind.
"We're not asking JK Rowling to start work on another novel tomorrow, we're just asking that she doesn't rule it out," said the chain's Wayne Winstone.
"The author has revealed that two characters will die in the forthcoming book, with speculation that one of them may be young wizard Harry himself.
Mr Winstone, the chain's head of children's books, said: "Harry Potter is a fictional character and therefore can't ever really be killed.
"Sir Arthur Conan Doyle famously killed off Sherlock Holmes, yet brought him back after years of demand from his fans and publishers. Couldn't the same happen for Harry Potter?
"Harry Potter is a global phenomenon, not just in the UK and the US, so aiming for a million signatures may prove to be conservative."
Almost 1.6 million copies of Harry Potter and the Deathly Hallows have been pre-ordered through online retailer Amazon.
Last week, JK Rowling said she felt euphoric but "devastated" as she wrote the last words of the last book.
The latest film in the series, The Order of the Phoenix, opens around the world from 11 July.