Despite the publication date not being known, the book is tipped to be a big seller, like the rest in the series.

Speculation about the plot has surrounded the book after Rowling admitted two characters will die - some think it could be Harry Potter himself.

Harry, 13, from Leicestershire emailed BBC Newsround and said: "It sounds interesting, but a bit sinister."

Kes Nielsen, for Amazon.co.uk, says "This is the first piece of the jigsaw in the final part of the Harry Potter series," he said. "The book's release will be met with an unprecedented level of excitement - but also a sense of sadness. Over the past 10 years, so many people have been enchanted by the world and characters that JK Rowling has created. It will be like saying goodbye to an old friend."

This week Rowling revealed how she has gone back to writing in cafes - as she did 13 years ago when starting to write about the boy wizard.

She has also admitted how she has been dreaming of the character.

Writing on her website she described it as an "epic dream" where she was Harry and the narrator simultaneously.

In a recent web posting, she said she has been working hard on the last book.

"I'm now writing scenes that have been planned, in some cases, for a dozen years or even more," she said.

Harry Potter and the Deathly Hallows is expected in early 2007.