SITTING behind a huge oak table surrounded by priceless literary treasures, Philip Pullman is in his element.

Among the gems on show in the Brotherton Library's hallowed Special Collections room, are childhood stories written by the Brontës and original illustrations by Arthur Ransome for his adventure classic Swallows and Amazons. There's also a first edition of Paradise Lost, a book that has arguably influenced Pullman more than any other.

The 63-year-old author has been invited to Leeds University to give a special talk to students about the art of storytelling and composition, a subject he is passionate about, especially when it comes to children's literature.

"Great literary theorists sometimes use children's books as a way of explaining what
they mean," he says. "But children's books are also interesting in themselves as examples of how words and pictures can work together, because the way they do is so fascinating and so inexhaustibly talkaboutable."

Pullman's first children's book, Count Karlstein, was published back in 1982, it was followed by The Ruby in the Smoke, which saw the introduction of Victorian adventurer Sally Lockhart. But it's his trilogy of fantasy novels, His Dark Materials, that has brought him fame and fortune.

For those unfamiliar with the books, they tell of an epic struggle between good and evil that centres around Lyra and Will, who come from alternate worlds populated by angels, ghosts and an armoured polar bear.

His trilogy has been acclaimed for its gripping plot and endlessly imaginative landscape. It also raises questions about the nature of hell and the existence of God, which has attracted criticism from some religious groups. But for Pullman, it's all about the story.

"When I write I want to finish the story I've started, I would like it to be read by as large an audience as possible, of course, but I don't want to specify the audience, I leave that to publishers and booksellers," he says.

"Some writers do know exactly who their audience is, but I don't think I do. I sort of guess that the audience will include children but will not consist entirely of children, and I like that."

There are those who feel that books like Pullman's are in danger of being swamped by the tide of interactive toys, computer games and dvds vying for children's attention today, although it's not a view he shares.

"The biggest publishing event in my lifetime was the last Harry Potter book that came out. The whole thing was quite extraordinary which just proves there is nothing so engaging, so involving, or so compelling as a book.

"It's much closer to your emotions and your imagination and children know and respond to this. If you look at the favourite book of a child who is lucky enough to be read to, it's battered and it's stained and the pages are bent because its been loved so much and absorbed into the child.

"I don't care how many people become electronic readers, books will never be replaced because they are so physically friendly."

He says he's always been a compulsive reader whether it was poems, comics, or novels. "It was essential, I was always telling ghost stories to my friends at school. I would read something in The Pan Book of Horror Stories and go in the next day and tell them about it."

This was one of the few outlets for his imagination. "There was no such thing as creative writing in schools, it didn't exist, you did an essay and if you were lucky the teacher allowed you to write a story and I used to love doing that, but it was not something seen as being important."

Pullman was brought up in England, Zimbabwe and Australia before his family settled in North Wales. A bright child, he went on to study at Oxford University. "I did an English degree because I always wanted to write and I thought if I read lots of nice books I'd learn how to write, but actually it didn't teach me a thing."

He spent 12 years working as a teacher during which time he began writing his first novels. "I didn't leave full-time employment until I was earning enough to live on, so I never had to starve in a garret."

He talks about writing as a craft, rather than a romanticised struggle between an artist and his muse. "I don't believe in writers' block," he once famously remarked. "Plumbers don't get plumbers' block; why should writers be the only profession that gives a special name to the difficulty of working, and then expect sympathy for it?"

He is equally pragmatic when it comes to film versions of his work. "It's one of the responsibilities of writers to earn a living and pay a mortgage and if someone offers you money to make a film of your book it would be high-minded to the point of absurdity to say, 'no, I can't have that'."

Which is why he had few qualms when Hollywood bosses wanted to turn Northern Lights, the first novel in his fantasy trilogy, into a blockbuster. The subsequent film, The Golden Compass, won an Oscar and boasted an all-star cast including Nicole Kidman, Daniel Craig and Sir Ian McKellen, but received a mixed reception at the box office.

"Unless you are particularly obsessive about the purity of your works then I don't see any harm in it and I think they did a good job with The Golden Compass," he says.

Pullman also wants to clear up the confusion surrounding the apparent changing of the book's name.

"Before it had any title at all I was looking through Paradise Lost for a phrase I could nick and in book four or five when Milton's describing God dividing the created world from the uncreated chaos outside, it says 'he took the golden compasses, prepared in God's eternal store to circumscribe this universe, and all created things.' And I originally called it The Golden Compasses because I thought that was an interesting phrase.

"That's what it was when I sent it to my publisher in America, but while talking to my British publisher we decided it should be called Northern Lights and that became the first part of His Dark Materials, which comes from somewhere else in Paradise Lost."

But by the time he'd settled on the new title, the American publishers had already started promoting the book as The Golden Compass.

"In most of the countries where the book's published it's called The Golden Compass so it made sense for the film to be called that."

As a famous writer, Pullman is often asked for advice by aspiring novelists. "The advice people are often given is study the markets, I say do exactly the opposite. What the market has been saying for the last 10 years is 'we want another Harry Potter', but no one was saying 'where's the first Harry Potter book?' The only person who was thinking about that was JK Rowling.

"So write what you want to write, because people don't know what they want to read. It's like politicians asking focus groups what they should be doing. If you're in politics you should know what you want to do."

His only real advice is to read. "Read everything you can get your hands on, in fact if you're not a compulsive reader you probably shouldn't be writing."