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.
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.
I can't see it happening, you can't force somebody to write a book anf if she kills off the main charcter that should tell people that she is probably done with Harry. Maybe she will go on to write about a new charcter that is as good as Harry Potter or maybe she will retire who can tell.
As they said Sir Arthur Conan Doyle caved into public pressure and brought Sherlock Holmes back from the dead so anything is possible.
If she did decide to write another Harry Potter book she wouldn't have to write a sequel to the seventh book she could write a prequel as it would still be connected to the Harry Potter story.
And anyway she could write about Dumbledores life after all she made a passing reference to Dumbledore defeating the dark lord Gindlewald so that could be a book in itself.
"there's only one way to win a war: shout, shout, and shout again!" - The Duke of Wellington ((Blackadder - Stephen Fry))
Based on the billions of dollars this franchise makes I'm sure Rowling knows the popularity of this character and a pettition really doesn't make a difference.
I hope she kills of the character and is done with it.
What is she going to do, write 50 of these books that gradually suck more and more until people get pissed and wish she hadn't written any more books.
Better to leave people wanting more than ruining the series.
I think this should be the last one and I don't think she will give into a petition. I think she is going by the golden rule in entertainment - give the people what they want but always leave them wanting more.