''There is a particular science fiction approach to the world, and it has nothing to do with the future. It doesn't have to be in the future at all. I used to read anthologies of science fiction stories when I was a kid – there'd be 10 stories about rocketships and ray guns, and then there'd be some strange Robert Bloch story set in some town in the 1950s that had no science, no traditional SF content, but in the mind of someone it was clearly science fiction. It had that SF approach: an awareness that things could have been different, that this is one of many possible worlds, that if you came to this world from some other planet, this would be a science fiction world.

''In Cryptonomicon, some of the characters have been going along and they've discovered a little crack in the sidewalk, it splits wide open, they fall through it, and they're in this whole universe that they didn't imagine. It happens for them in different ways. The clearest case is Bobby Shaftoe, who is minding his own business having a career in the Marine Corps and suddenly everything becomes very, very strange for him. It takes him a long time to figure out what's going on, and he never totally gets the whole story.

''I wanted to have, as kind of a running theme, a fictitious ancient book that was a compendium of all known crypto lore. The idea is that each generation of cryptolotists that comes along picks it up and adds onto it, so at any given point it's everything, the whole body of knowledge about crypto. I wanted to give it a title a 17th-century book by a scholar would be likely to have. And that's how I came up with Cryptonomicon. I've heard the word Necronomicon bounced around. I haven't actually read the Lovecraft books, but clearly it's formed by analogy to that.

''Like a lot of people, I went through a period of reading science fiction exclusively. I joined the SFBC, and would just spend days reading. My favorites were always Norton and Heinlein. Particularly the way Norton would mix things up and have them happening in the very far future but with ESP or magic or something. It was really mind-expanding for a kid at that age. I liked The Zero Stone, and the other I really liked that I remember really clearly is Have Spacesuit, Will Travel. I read that over and over. I stopped reading SF for a long time, in high school, college. Rightly or wrongly, I didn't think there was much to be read. Then when Neuromancer came around, it was a real thunderbolt for me, because I had gotten interested in writers who had a really vivid style – Hunter Thompson, Tom Wolfe – and if I was going to be a writer, that was how I wanted to do it. Then to see that really vivid, literary style of writing in a science fiction book, and not a space opera but something set on the surface on the Earth, and have these noir overtones, to me it was an amazing synthesis of several things I was interested in.

''[When I wrote The Big U] it was July, and the weather was boiling hot and humid. There was no air conditioning, so I'm sitting there in my underwear, pounding this thing out as fast as I can go. The plastic backing of the carbon film ribbon was actually softening in the heat, and if it stopped moving, it would adhere to the guides it was threaded through and seize up, and I would have to completely disassemble the typewriter and get it unstuck. So there was this huge incentive not to ever stop typing. That manuscript is full of these long, rambling, incoherent sentences, which were probably just me typing in order to keep the ribbon moving! Later, of course, it came in for some heavy editing.

''I was writing Snow Crash about the same time my uncle, George Jewsbury, and I started talking about doing collaborations. The rationale behind that was, clearly, I may be able to limp along indefinitely, writing these little books that get bought by 5,000 people, but really it would be smart to try to get some kind of serious career going. We had heard somewhere that Tom Clancy had made like $17 million in a year. So we thought, 'Let's give this a try.' The whole idea was that 'Stephen Bury' would be a successful thriller writer and subsidize my pathetic career under the name Neal Stephenson. It ended up going the other way. I would guess most of the people who have bought the Stephen Bury books have done so because they know I've written them. It just goes to show there's no point in trying to plan your career.

''Originally, I planned to have storylines in Cryptonomicon set in the present, past, and future, but I pulled out the one set a couple of generations in the future – more the kind of stuff that people are accustomed to seeing from me. Though it previously looked as though it was going to be kind of sparse, now it was looking like it could stand on its own, but it would take a lot more time and work. And yet the WWII and present-day timelines were done, and it seemed crazy to hold up the entire thing any longer for the future one to get done, so we could bring that out first. So we decided to take this approach. Besides, the book was already at the limits of size! The future scenario will be a later book.

''I have two sequels to Cryptonomicon planned, but they're in different time lines. I'm trying not to give the idea that it's a tightly locked together set of books. They're supposed to work as stand-alones. There are always a few strange little corners of the story that may not make sense outside of the context of the full series, but 99% of it can stand on its own reasonably well, I hope. It's kind of a wink to the science fiction readers out there: 'See, it really is a science fiction book!' ''