Fantasy writer Brandon Sanderson tells David Larsen how a dragon on a book cover lured him back to reading and changed the path of his life.

You know that feeling when you finish a good book and you wish it wasn't over? "I wish that book had been 100 pages longer," you think. Well no, you probably don't, because that would have meant 100 pages of padding. A good book defines its own proper length. But wouldn't it be nice to find a good book whose proper length was really, really long? Let me introduce you to Brandon Sanderson.

"You know, I trimmed it a lot. It's the right length. It's the length it needs to be. It's fair to say it is not a small book." Sanderson is talking about The Way of Kings, his latest novel. It is, and let's just fixate on this for a moment, very long, indeed.

One of my favourite New Zealand novels, Nigel Cox's The Cowboy Dog, is about 60,000 words long. If you put six copies of The Cowboy Dog between one set of covers, The Way of Kings would still be longer. The first time Sanderson showed it to a publisher, the response was a shaky, "Do you know what getting this thing printed and bound would cost us?"

Sanderson laughed, and offered the publisher three smaller books instead. Those three books made his name, attracted a very scary phone call, and made The Way of Kings a viable publishing proposition. But let's back up a little.

"I grew up in Nebraska. I read quite a lot when I was little, but by high school I was not a reading sort of kid. Some kids read, I watched TV. People would shove books at me in school and I just wasn't interested. Then, when I was 14, I had this one teacher, called - I swear I'm not making this up - Mrs Reader. And she said, 'look, you are going to read a novel, and you are going to write me a book report. I have a box of books in the back room. Go on back there and pick one. Take your time.'"

One of the books had a rather fabulous picture of a dragon on the cover. Never let anyone tell you cover illustrations don't matter. It changed Sanderson's life.

"I devoured that book, which was by Barbara Hambly. I couldn't believe there was this entire type of novel that no one had told me about. I went to the library and checked out every fantasy novel I could find, read them voraciously over the summer, fell in love with the genre, decided within a year that I wanted to be a writer, and started working on my first book. Which was atrocious, but fortunately I didn't know that."

While majoring in English at college, Sanderson took a job as a hotel receptionist, working the graveyard shift.

The managers didn't mind if he wrote on the job. "In fact, they were happy if I did, because that meant I wasn't falling asleep like the previous person they'd hired. So I wrote - oh gosh, it must have been nine or 10 novels over the course of five years."

Sanderson was living one of the standard writer-learns-the-ropes stories - turning out book after book after book, finding his voice, finding the stories that mattered to him, and finding the self-belief to swallow the rejection letters. There were a lot of rejection letters. He made his way through the forest of fantasy and science fiction sub-genres, one at a time. "I did a post-apocalyptic book, I did an epic fantasy, I did a comic fantasy, I did some cerebral science fiction, I did a short action adventure fantasy..."

No one wanted any of them. In frustration he tried to figure out what kind of books publishers were looking for, so he could write one.

"We call this chasing the market and it's a bad idea. I knew it was a bad idea and I did it anyway. The next two books I wrote were the two worst I'd done. I mean, I'd learned something from all those unsold novels and technically they were okay, but they didn't have any soul, they were just dreadful books. I didn't even send them out."

Instead he sat down and deliberately wrote something profligately, ridiculously unpublishable. "I had to say okay, I'm a writer, I love it, this is what I do. Getting published is not the aim. Writing is the aim. So okay. I'm going to ignore what everybody's been telling me in these rejection letters. I'm going to write the biggest, coolest, baddest, most awesome fantasy epic I can. All these ideas that I've told myself are too big, that I'm going to have to put off using, I'm not going to put off any more. And I sat down and I wrote The Way of Kings. I sank everything into it. I created this awesome beast of a novel, and to be perfectly honest, my skill wasn't up to doing it justice at that point, but I gave it everything I had."

The Way of Kings is a broad-canvas cinematic story, but it's also an intimate exploration of some of Sanderson's central themes: what leadership is, whether idealists can put their ideals into practice without betraying them, and whether people of good conscience can overcome their religious and political differences. Very much a book of the American moment, in other words.

Like all his others, it didn't sell. But one of his earlier books suddenly did.

This was the point where the people he could now describe as his publishers asked what else he was working on, and he told them, and they blanched. So he offered them a more conventional project, taking some of the ideas he'd developed for his two loathed market-chasing books, and reworking them into what became his Mistborn fantasy trilogy. This got extremely good reviews and led to a phone call from Harriet McDougal, the editor and widow of the fantasy writer Robert Jordan.

Jordan had been the big fantasy sensation of the 90s. His mega-series The Wheel Of Time began as a five-book cycle, then was expanded to a projected 12 books on the back of massive sales and critical acclaim. Each individual book was vast. The gaps between books slowly got longer and longer as Jordan struggled with gargantuan plot machinery, a cast of thousands and failing health.

He died in 2007, still working on the final volume, and McDougal, having been impressed by the Mistborn books, phoned Sanderson and asked whether he would be interested in finishing off the series from Jordan's notes.

"She called me out of the blue and, dumbfounded, I said yes. I mean I was a huge fan of Robert Jordan, how could I not say yes? But I was terrified. And I rightly should have been."

Sanderson has spent much of the last three years on the Jordan project, which has involved splitting an unworkably huge manuscript - Jordan made extremely detailed notes, fortunately for worried fans of the series - into three parts, each of which will become a 300,000-word novel. The second of these is due out in New Zealand this month.

Meanwhile, Sanderson has also found time to go back and rewrite The Way of Kings and sell it to his publishers, who by this time were very glad to take it.

It's worth mentioning here - "though my publisher would rather I stopped talking about this, they think it's off-putting" - that he had always intended it to be volume one of a 10-book series, The Stormlight Archive, each book of which will be about the size of the first.

"The thing about fantasy novels is that they start off with a very steep learning curve. They're like historical novels, except that the world is entirely invented. You have to learn new names, you have to learn new laws of physics, new geography, new history, all of these things.

"This is what fantasy readers love, but when you're making the effort to master all this information it's nice to maximise the payoff. That's what a big series has that a shorter series doesn't, it can be far more richly immersive. You get to spend serious time in this new world."

In other words, even before he was tapped to complete Jordan's magnum opus, Sanderson was setting out to be his generation's answer to Robert Jordan. Is he not worried, with nearly four million words of projected storytelling ahead of him on this series alone, that he may meet a similar fate?

"I'm still pretty young. Plus, I live in perpetual fear of this distant cubicle far behind me. Some day I worry it will catch me and I'll have to become an insurance salesman or something. So I tend to work pretty hard. My hope is that I'll be releasing two of these books every three years. There'll probably be a third book in there as well, something smaller to keep me fresh. We'll see."

The Way of Kings (Gollancz $34.94); Towers of Midnight, the penultimate novel in Robert Jordan's Wheel Of Time (Orbit $42.99)