"In my wildest fantasy I could not have imagined anything like this", JK Rowling said of the frenzy that has surrounded the release of her last book, Harry Potter and the Goblet of Fire, the fourth in the series of seven.

Her wild fantasies of wizards and witchcraft have prompted the biggest publishing sensation of modern times.

Joanne Kathleen Rowling dreamed up the story of Harry Potter, the bespectacled orphan blessed with magical powers, on a train trip between London and Manchester.

It has been a high-speed journey. Less than eight years ago she was on the dole, scribbling away her first Potter draft in an Edinburgh café dreaming of the day she could take up writing full time.

Now she is a publishing phenomenon, with the series selling over 100 million books, translated into 42 different languages, around the world. In 2001 alone she is estimated to have made £70m.

'Ridiculous things'

Dreams come easy to JK Rowling. Though born in Bristol, she grew up in the Forest of Dean on the Welsh borders, whose most famous son was another Potter, Dennis.

In a scene reminiscent of his Blue Remembered Hills, JK Rowling recalls: "We couldn't do what urban kids do, so we were out making up ridiculous things in the fields."

After graduating in French and classics at Exeter University, she took up a post teaching English in Portugal. She met and married a Portuguese journalist, Jorge Arantes, by whom she had her daughter, Jessica.

But the marriage did not last and she moved to Edinburgh to be near her sister when Jessica was four months old.

Times were hard. Rowling suffered clinical depression.

She admitted that the Dementors in Harry Potter and The Prisoner Of Azkaban, dark hooded creatures that suck out their victims' personalities by identifying their secret fears, were based on the dark feelings of her illness.

But to the uninitiated, the Harry Potter books are anything but depressing. They revolve around the hero who attends a school for wizards in a vast castle near a huge lake and a dense forest.

They are old-fashioned tales of good versus evil with strong, twisting plots, thrills and spills and a vocabulary all of their own.

Marketing

The author is not without her critics. One dubbed her work "Billy Bunter on broomsticks".

The author Anthony Holden led a faction which prevented her winning the prestigious Whitbread Prize for literature in 2000.

He derided her work as having merit "scarcely higher than a Spice Girls lyric". Her characters, he said, were "one-dimensional" and her appeal a product of over-hyped marketing.

The word arrogant has been levelled at her. She refused to allow the BBC to abridge her work, an unprecedented move - but that encouraged Radio 4 to broadcast Stephen Fry's eight-hour reading of The Philosopher's Stone on Boxing Day 2000.

From a literary viewpoint, Anthony Holden's criticism seems mean-spirited. JK Rowling's books are easy to read, imaginative, and, even if they are not entirely original, they are enchantingly gripping.

In a child's world dominated by computer games and videos, the author has managed to appeal to both sexes and has raised the profile of children's writing. What is more, kids find her books funny.

"Rowling's comic timing is brilliant, perfect", says Times literary critic Nicolette Jones.

"Her books are beautifully paced and are a mixture of school magic and beyond. They'll be bought by future generations of children, and adults too."

At Christmas 2001, Rowling married her partner Dr Neil Murray in a quiet ceremony at her home in Perthshire.

The author guards her privacy fiercely, and in October 2001 won a complaint against a magazine which published pictures of a family holiday.

Phoenix

For now, life is getting better and better for Rowling.

She has finally won a three-year lawsuit in which she was accused of stealing ideas for the Potter books from American author Nancy Stouffer.

And she and Murray are expecting their first child early next year.

Meanwhile, her loyal audience awaits the fifth book in the Potter series, more than two years after Goblet Of Fire was released.

Rowling says she has almost finished the novel, Harry Potter And The Order Of The Phoenix, and it should be arriving in bookshops some time in 2003, although no date has been set.

Untimely death

She has dismissed reports of "writer's block", which surfaced after the fifth book failed to materialise in 2001, saying it was never her intention to write all the Potter books quickly.

The fact that she has the plots for the remaining novels already sketched out suggests Rowling is still very much in control of the series.

She recently revealed she had the final chapter of the final book already written, and promised some major plot developments in the remaining books.

There have even been hints that some of the main characters may be facing an untimely death.

But with the first four books still in the bestsellers list, and the second Potter movie released in November 2002, the Potter phenomenon looks set to run and run.