JK ROWLING’S publishers will launch a renewed bid to sell her first four Harry Potter books to grown-ups this summer, issuing them for the first time as "adult hardbacks".
Bloomsbury Publishing hopes that the newly designed covers will see the further development of the "kidult" or "crossover" market for children’s books that Rowling herself is largely credited with creating.
The Harry Potter sensation has not only seen the almost unthinkable phenomenon of ten-year-olds battling through 700-plus page books such as Harry Potter and the Order of the Phoenix; it has also helped carve a new marketing niche into which authors like Philip Pullman and Mark Haddon have stepped.
But Bloomsbury says the potential of adult crossover sales "is largely untapped in the UK and export markets". It will use the new hardbacks in an effort to relaunch its earlier "adult paperbacks".
The move may also reflect the fact that the massive sales of the Potter books mean they are already in most families’ homes.
"Every child in the UK probably now has a copy of Harry Potter so this is a way to get to the adults as a new-look hardback," said Kathryn Ross, of the Edinburgh-based literary agency and consultancy, Fraser Ross Associates.
Tom Holman, a publishing reporter for The Bookseller who closely tracks book sales, added: "There’s huge potential there for more adults to read them. I don’t imagine there’s any room to grow in the kid’s market."
This is the first time the cover designs, by Bloomsbury’s design director William Webb, have been printed in a newspaper.
Mr Webb designed the first adult paperback jacket of Harry Potter and the Philosopher’s Stone, featuring simple black-and-white images of cars or trains, more sombre and grown-up than the familiar boy with round glasses.
About half Bloombury’s sales come from the Harry Potter titles; while the company’s pre-tax profit was up 38.3 per cent to 15.38 million in 2003, after a decade of booming growth, the company’s relatively low share price is said to reflect questions about what comes next.
A Bloomsbury spokeswoman said the children’s editions are "still selling very strongly in the UK", while worldwide sales of JK Rowling are now over a quarter of a billion books.
"The older readers are sticking with it; they’ve been fans since the beginning, and their younger brothers and sisters are coming through," she added.
The books will get a boost from the June release of the film of book three, Harry Potter and the Prisoner of Azkaban, and a marketing campaign to "ensure the sustainability of the series for many years to come", the company said.
Harry Potter and the Order of the Phoenix, published last June, was the first in Britain to have separate hardback covers for adults and children.
In 2003, the children’s version sold close to three million copies, the adult version about 400,000. This was a "fantastic" sale that by itself was the ninth-biggest seller of the year, said Mr Holman.
The earlier books were all published in adult paperbacks, with a slight delay.
"All the publicity around Harry Potter attracted adults as well as kids," Mr Holman added. "It will be interesting to see how these new adults do. There’s definitely the potential there. Once kids’ books lose that kind of stigma, it snowballs. Adults tell their friends and sales increase.
"Five to ten years ago you wouldn’t catch any adults reading kids’ books, but Harry Potter has definitely changed that. It’s been a big shift and the Potter books are in the vanguard."
Crossover marketing is about more than a book’s cover; children’s and adults’ books are often marketed by different agents, sold and distributed by different publishers or divisions of a publishing conglomerate.
Children’s books traditionally stayed out of adult book reviews and best-seller lists. Bookshops and libraries also have separate budgets and sections.
In 2002, for the first time, Philip Pullman, a children’s author, won the Whitbread Book of the Year prize with The Amber Spyglass, part of the trilogy His Dark Materials.
But it is the phenomenon of dual marketing in particular that appears to be new.
Last year, Mr Pullman’s book Northern Lights sold 200,000 in its children’s edition and 43,000 in the adult version.
Mark Haddon’s gripping narrative of an autistic boy, The Curious Incident of the Dog in the Night-time, won the Whitbread prize this January.
It was originally signed up by the children’s editor at Random House, but the company’s adult publishing arm Jonathan Cape then launched its own "grown-up" edition - which outsold the children’s edition by three-to-one, about 150,000 copies to 50,000.
"Children’s publishing traditionally takes children to the age of 14 or 15. Beyond that it is adult publishing," said Ms Ross, whose firm’s clients include the prolific children’s author Vivian French. "Adults have discovered that books being published for children are very good."