It is not just JK Rowling who has been working hard on Harry Potter over the past few years.
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Thousands of Potter devotees have explored the world of Harry Potter by writing their own "fan fiction" that fleshes out the lives of both major and minor characters from the books.
Much of the fan fiction is short stories but there are also short novellas and even entire books that rival JK Rowling's work for length.
Popular Harry Potter websites act as showcases for these literary works giving budding authors a ready audience willing to read and criticise their creations.
Many say that writing fan fiction has helped them cope with the long delay between the appearance of the fourth book and the much-anticipated Order of the Phoenix.
"There's certainly a lot of anticipation for the book and this is an outlet for that anticipation," said Claire Field, who runs the Harry Potter Guide website.
Jennie Levine, spokeswoman for fan fiction site Sugar Quills, agreed: "I definitely think that the fact that this is an unfinished series spurs on the desire to write fan fiction."
The delayed fifth book has led people to speculate about which way the story will go before the proper text appears.
Severus Snape has inspired lots of fan fiction.
"People write fanfic to explain a theory about where the books' plot and characters will go, or where they're coming from," said Heidi Tandy, one of the administrators on FictionAlley.net.
JK Rowling herself has said that some of the ideas put forward by fans have come close to the direction that she has mapped out for the series.
Part of the appeal of the books is the inventive, coherent and complicated world that JK Rowling uses as a backdrop to the boy wizard's adventures.
Many fan fiction writers are happy to explore this world with their own stories and often use tiny incidents in the books as a spur for their own creations.
Jennie Levine from Sugar Quills said one writer took one sentence from a Harry Potter book about how the hapless and clumsy Neville Longbottom character discovered he was a wizard, and turned it into an entire story.
But, she said, many fan fiction writers avoided writing about Harry Potter.
"If you can't capture Rowling's style and tone in that situation, then the story will often ring false," she said, "Also, we know a lot about Harry, so people tend to become fascinated with other characters, where it is easier to fill in blanks"
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Some writers spend a long time exploring the off-page life of a major character such as Severus Snape, the potions master who nurtures a dislike of Harry. One story about Snape has stretched to 76,000 words.
The fact that actor Alan Rickman plays Snape in the films may have prompted many of the stories written about the potion maker.
While many people are happy to keep within the broad confines of Harry Potter's world and with events that may have happened, others, said Shayna Ingram who runs the Harry Potter Realm website, venture off into "wild speculation."
"These stories," she said: "are an outlet for fans to be able to express what they'd like to happen in the series."
Often, said Ms Ingram, these stories give alternative lives for key characters such as Draco Malfoy or bring in entirely new characters, events and plots.
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While some of these work well, said Ms Ingram, others are thinly disguised wish fulfilment and are hard to stop descending into cliché.
She said many of these so-called "Mary-Sue" fan stories involve American exchange students who turn out to be smarter than Hermione and always manage to snare the object of their affection.
"At the core of it all, I think of fanfiction as a way to live in and extend the world of the characters we love," she said, "kids and adults alike write fan fiction to further immerse and lose themselves in a world of imagination, fantasy, and dreams."