Neil Gaiman has published the unabridged text of an interview he did with Stephen King for the Sunday Times (an abridged copy is also available somewhere behind the Times's paywall). Gaiman really gets at the core of what King does, and offers a glimpse into what makes him tick:
I never thought of myself as a horror writer. That’s what other people think. And I never said jack shit about it. Tabby came from nothing, I came from nothing, we were terrified that they would take this thing away from us. So if the people wanted to say “You're this”, as long as the books sold, that was fine. I thought, I am going to zip my lip and write what I wanted to write. The first time that anything like what you’re talking about happened, I did this book Different Seasons, they were stories that I had written like I write all of them, I get this idea, and I want to write this there was prison story, “Rita Hayworth and the Shawshank Redemption”, and one based on my childhood called “The Body,” and there is a story of this kid who finds a Nazi, “Apt Pupil”. I sent them to Viking, who was my published my editor was John Williams – dead many long years - terrific editor – he always took the work dead level. He never wanted to pump it. I sent them Different Seasons, and he said well, first of all you call it seasons, and you have just written three. I wrote another one, “The Breathing Method” and that was the book. I got the best reviews in my life. And that was the first time that people thought, woah, this isn’t really a horror thing.
I was down here in the supermarket, and this old woman comes around the corner this old woman – obviously one of the kind of women who says whatever is on her brain. She said, 'I know who you are, you are the horror writer. I don’t read anything that you do, but I respect your right to do it. I just like things more genuine, like that Shawshank Redemption.'
“And I said, 'I wrote that'. And she said, 'No you didn’t'. And she walked off and went on her way.”