By Simon Atkinson
Business reporter, BBC News
Among the many financial beneficiaries of the Harry Potter phenomenon, Dean Taylor is perhaps the most unlikely.
JK Rowling finished writing the final book in January 2007
On the back of JK Rowling's literary sensation, the 42-year-old has conjured up a comfortable niche working as a lookalike of the teenage wizard's enemy, the villainous Lucius Malfoy.
If and when the Potter craze dies down, Mr Taylor will not be too worried about being able to put food on the table - not least because he is also hired out as an impersonator of Black Sabbath frontman Ozzy Osbourne.
But there are plenty of others - not least the books' readers and its publishers - who may find adapting to life after Hogwarts a little less easy.
It has certainly been an incredible ride - perhaps more exciting than even the most competitive game of Quidditch - and a profitable one at that.
Since Ms Rowling was paid a £3,000 advance in 1995 for Harry Potter and the Philosopher's Stone, which had a print run of just 500, more than 300 million copies of the six Harry Potter books have been sold.
And this Saturday, many bookshops will open at midnight to satisfy demand for the final novel, the 608-page Harry Potter and the Deathly Hallows, which will bring to an end the tales of the wizard's adventures.
Of course, it is the author who has been the biggest winner. Estimates put her wealth at close to £550m, making her the first dollar-billionaire author.
Harry Potter stamps are just another extension of the brand
But plenty of others have ridden the wave of wizardry - not least her literary agent, who is thought to have reaped more than £50m.
Meanwhile, two accompanying books by Ms Rowling, Quidditch Through the Ages and Fantastic Beasts And Where to Find Them, have raised more than £15m for Comic Relief.
For UK publisher Bloomsbury - and Scholastic in the US - Harry Potter has been that rare thing: a book which has crossed cultures, bringing words such as "muggle" into the common vernacular.
The debut novel has been translated into about 65 languages, highlighting its international appeal.
Indeed, Bloomsbury has said that pre-sale orders for the new book were high - up 17% on the previous edition - partly because so many learners of English around the world were buying it.
In China alone, sales were up 226% in 2006.
Inevitably, Bloomsbury has also announced plans for audio CDs and a seven-book box set, as it tries to eke out every bit of the Potter magic it can for its balance sheet.
It is an indication of how crucial the books have been to the publisher that its annual profits dropped 74% in 2006 - a Potter-free year.
While the new books may cease, the sales are expected to continue, although at lower levels.
"This is the last generation that actually had to wait for each book to come out, so they're going to have a special relationship with Harry," popular culture historian Robert Thompson of Syracuse University told the USA Today newspaper.
"But for at least another century, every year a new batch of kids will be introduced to Harry Potter. There's always going to be a new kid turning eight years old."
The end of the series is a problem that Bloomsbury has faced for some time as it tries to sign new deals to plug the inevitable gaps, analysts say.
"Harry Potter remains a key ingredient in the group's future success," said Keith Bowman of Hargreaves Lansdown Stockbrokers.
Rowling says she is excited by the idea of a Harry Potter theme park
"Management now have to look beyond the initial euphoria created and on balance, the jury is still out as to whether it can inject the necessary levels of diversification needed in the highly competitive publishing world."
Given that it showed faith in Ms Rowling during the early days, shareholders will be praying that the author will stay with the firm, should she stick with her plan to write further, non-Potter books.
So keen are retailers to extend the series - and, just maybe, the sales, too - that Waterstone's has launched a "Save Harry" campaign, complete with petition.
Both it and WH Smith are planning some heavy discounting on the seventh book, while online seller Amazon has already reported pre-orders of close to two million copies.
Meanwhile, Tesco and Asda are to sell the book at almost £2 less than booksellers are paying for each copy at wholesale price - the equivalent to almost half the recommended retail price.
'Created a buzz'
Even though they cannot compete on price, some independent booksellers feel they have benefited from the Potter charms.
"We do sell some copies, we'll open at midnight on Saturday and expect to have a bit of a queue," said Lesley Agnew, manager of the Children's Bookshop in Muswell Hill, north London.
"But in terms of a percentage of our overall sales, Harry Potter means nothing to us really."
However, Ms Rowling's creation had been important in tempting younger readers into the store.
Retailers such as Amazon have been stockpiling the latest book
"Over the years, it has been good in encouraging children to be enthusiastic about books, and has created a buzz, so in that regard, it has been good for us," Ms Agnew said.
"The challenge for the independent bookseller is finding books for the child who has finished reading Harry Potter."
Fun and games
While the books are nearing their end, there is still plenty of life in the Potter films, which have all been made and produced in Britain.
Recent release Harry Potter and the Order of the Phoenix - based on the fifth book - earned £166m ($330m) at the box office in its first week, the best worldwide debut for a Harry Potter movie.
To date, the films based on Ms Rowling's books have made an estimated £1.75bn in ticket sales globally, with Daniel Radcliffe, Rupert Grint and Emma Watson set to reprise their roles for the big-screen versions of the final two books.
UK Film Council figures show Harry Potter and the Philosopher's Stone to be the biggest-grossing UK film of all time at UK cinemas.
The productions have boosted visitor numbers at some of the key film locations, such as Alnwick Castle in Northumberland.
Even Harry Potter stamps have broken records to become the most anticipated Royal Mail special stamp collection, receiving more than 300,000 pre-orders.
And then there has been the merchandise, from the action figures and chess sets to the vibrating Nimbus 2000 broomstick.
At the peak of the phenomenon in 2002, more than £25m worth of Harry Potter toys were sold in the UK, beaten only by Barbie, said Wendy Janssen of market research firm NPD.
"It has fallen back a bit now, and I'm not sure why, but certainly Harry Potter has been a significant player in the toy market," she added.
The first Harry Potter film was released in 2001
The next big development is The Wizarding World of Harry Potter, a giant theme park planned for the US resort of Orlando in 2009, promising "an extension of Harry's world".
Visitors will be able to take in the village of Hogsmeade and the Forbidden Forest, as well as meeting the colourful characters who have driven the sensational stories.
Perhaps if Ozzy Osbourne's appeal begins to wane, Dean Taylor will be applying for a job there.