J.K. Rowling no longer wears the red tresses that became familiar to millions when her fictional creation, Harry Potter, launched her into the stratosphere of international media fame. She has dyed her shortened locks a generic blond, leaving the dark roots showing.

Woman's privilege, we wonder. But no: the long red hair and bangs were making her too recognizable, she says.

The new look frames intense, dark eyes and a pale, serious face. Here on one of the most lavishly hyped publicity tours in literary history, she has just handled a half-hour question session with a group of selected children, and another half-hour of polite but mostly lackadaisical quizzing by the Vancouver media.

She's an old hand at this by now. The fourth book in the series, Harry Potter and the Goblet of Fire, has just been launched, with hardback sales in Canada alone topping a million. Superstar? Of course, but there's a no-nonsense, unpretentious air about the way she handles herself.

Most of the questions have been asked a million times, but she fields them all with courtesy and good humour spiced with a tart British wit.

Now I'm getting 15 minutes of exclusive interview, one on one, and, given the constraints of time, I decide to focus on a topic that has been becoming increasingly important as the four books have appeared: the moral significance of the stories, and the proper use of power.

If you've been keeping abreast of the Rowling news, you'll recall that she has repeatedly come under fire from some parts of the religious right for writing about wizardry and witchcraft, and for portraying the endless conflict between good and evil through boldly etched fantastical characters.

Harry Potter, a student at Hogwarts School of Witchcraft and Wizardry, is constantly thrown up against dark forces, particularly the ultimate evil, Lord Voldemort.

So far, despite all the odds, Potter and the forces of virtue and decency have triumphed. The moral significance seems clear.

''It does to you,'' says Rowling. ''And to me it's so blindingly obvious. But when this first became an issue I would take an enormous amount of time to explain what I thought was so obvious.

''Now I am starting to get impatient because I feel that you can lead a fool to a book but you can't make them think. And you can quote me, actually, because I'm just getting impatient about it.''

It's the testiest she has been all morning. But you can hardly blame her. The books can hardly be clearer about her intentions. At the end of the latest, one of the forces of good, the Hogwarts headmaster Dumbledore, laments a death that has happened and says:

''Remember, if the time should come when you have to make a choice between what is right

and what is easy, remember what happened to a boy who was good

and kind and brave, because he strayed across the path of Lord Voldemort.''

That, says Rowling, was the key for her: the choice between what is right and what is easy, ''because that, that is how tyranny is started, with people being apathetic and taking the easy route and suddenly finding themselves in deep trouble.''

This, she said, was the first point at which she cried during the writing of the series.

Even the chapter in the first book that (she realized later) was based on her mother's death, ''even that didn't make me cry; I had never cried until I wrote that.''

That sense of moral responsibility, does she see it making Harry a moral figure for kids to emulate?

''I see him as a good person but with a human underbelly,'' she says. ''He is vulnerable, he is frequently afraid, he has a very strong conscience, and it is my belief that with the overwhelming majority of human beings -- maybe I'm a wild optimist -- most people do try to do the right thing, by their own lights.''

He sounds, I tell her, like a definition of Rowling herself, though she usually tells interviewers she's most like Harry's chum Hermione. ''Yes,'' she admits, ''there's an awful lot of me in Harry, but probably me as I am older. Harry is an old soul, and you meet children like that.''

Harry, of course, is able to battle supernatural evil with supernatural forces of his own, and Rowling is quite clear that she doesn't personally believe in that kind of magic -- ''not at all.'' Is she a Christian?

''Yes, I am,'' she says. ''Which seems to offend the religious right far worse than if I said I thought there was no God. Every time I've been asked if I believe in God, I've said yes, because I do, but no one ever really has gone any more deeply into it than that, and I have to say that does suit me, because if I talk too freely about that I think the intelligent reader, whether 10 or 60, will be able to guess what's coming in the books.''

A plank in the Rowling mythology is the fact that outlines for all seven books planned for the series have been firmly laid down since she began to write the first; she has even written the last chapter of book seven. Why spoil the fun?

So we talk about power, which seems to be at the basis of the tales: magic power, the power of parents over kids, the struggle between the power of good and the power of evil -- ''yes,'' she says excitedly, ''abuse of power, why people would seek power.''

And I ask her a personal question: given that in our society money equals power, and serious money (Harry has made her the highest- earning woman in Britain) equals serious power, how does she want to use that power?

''I've started using it,'' she says, referring to the $1.14 million Cdn she recently gave to an English charity for single parents. ''And fame also can equate with power. So I've started using both where I feel I can make a difference.''

Single parenthood is an issue close to her heart; since the collapse of her marriage in the early '90s, she has raised her daughter Jessica, now seven, alone.

''It's something that cuts across every walk of life and every kind of background -- ethnic, socio-economic. . . let's be frank, it's mostly women who find themselves in that position. And I used to wonder when someone would stand up and tell it like it was: Say 'No, actually, we're not all feckless teenagers who didn't know how to use contraception,' -- a view which was very prevalent in the media at the time, partly because we in Britain had a right-wing government that was very fond of scapegoating single parents . . .

''Most of us are people in committed relationships that went wrong. We also have to include all the people who have been bereaved who are tarred with the same very negative brush. The next heir to the throne is a single parent.''

She was reluctant to take on the advocacy task (''in all honesty I'm fighting for writing time right now, and I'm just wanting, number one, to see my daughter'') but she thought, well, ''someone's got to do it, so it's you.''

Although she has the kind of money these days that would allow her to consign her child to all kinds of comfortable care, she looks after her herself, taking her to school each day, though a nanny collects her in the afternoon and looks after her until 5 p.m., ''which gives me a full writing day.''

Jessica has read all the Potter books, says Rowling, ''and she read the latest all by herself . . . until chapter 30.'' That's when the book turns dark and violent, and Rowling decided she would read it to her: ''She needed support through that ending. It's the darkest book yet.''

Next in line from the Potter mill is the Harry Potter movie, and (I'm getting wind-up signals now from the publicity folk: I've already stretched the 15 minutes to 20) I ask her a question my 13-year- old nephew Tom e-mailed from England: ''Do you think the new film could ruin children's images of Harry and Hogwarts and make the next books less enjoyable because of the definite image of both characters and the school?''

The answer is a definite no, and at the same time a strong affirmation of her belief in her readers.

''If people have already invented Harry in their imagination, I would be very surprised if the film could disturb that. No film has ever ruined a favourite book for me, ever. It is my belief that my readers will be able to differentiate between the film Harry and real Harry and I think they will be in no doubt about who is the real Harry. People greatly underestimate children.''