Science was one of those things (music was another) that I was fascinated by at home, and turned off by at school. Like many children who grew up in the 1950s, I read that great comic the Eagle every week, with the adventures of Dan Dare and his enemy, the Mekon; and one of the items I most enjoyed was the science feature, the explanation of such things as radar, or nuclear fission, or rocket propulsion. There was a comic-strip character called `Professor Brittain`, a genial sort of boffin, as they used to call scientists, who explained it to a suitably wide-eyed boy and girl. I soaked it all up greedily.
Then there were our trips to the Science Museum in South Kensington. What a wonderful place that was, and still is! Photoelectric cells and calculating machines, pulleys and radio valves - I didn't understand much of it, but I loved it all. It meant excitement and wonder and amazement; it meant the sense that anything was possible, and that the universe was huge and full of exciting things to discover.
So why didn't I like science at school?
One reason might be that although I'm a science fan, I'm not fundamentally a scientist. I'm a storyteller. A genuine scientist would love the subject for itself: I think I love science for the stories that are told about it. I can't do the hard stuff; mathematics is a horrible struggle; but let Professor Brittain begin to explain gravity or nuclear radiation or how the solar system was formed, and I'm spellbound.
I think there are many people like me, who love hearing about something we can't ourselves do. Those of us who enjoy reading about science are living in a lucky time. There has been a great wave of very good writing about science in recent years; it's easy now to find books on geology, or evolution, or physics, or genetic engineering, or all sorts of other sciences, which are brilliantly written and as exciting as any thriller.
And among the very best of the modern writers on science are Mary and John Gribbin. I have read many of their books; I've heard John lecture; I've learned an enormous amount from them. When I heard that they were interested in writing a book about the science of His Dark Materials, I felt as privileged as if Dan Dare had invited me for a flight in his rocket.
But I wondered what they'd find to say... Because I wasn't writing about science, after all. I was writing about Lyra, and Will, and Mrs Coulter and Lee Scoresby and Mary Malone and all the other characters; and although I did try to get a bit of science in, and to get it right, it was very much there as a background, as a sort of stage set for the story to take place in front of.
Take the idea of parallel worlds. Many writers have used this idea, though it doesn't always come with a scientific explanation. Lewis Carroll's Alice books both begin with Alice leaving her world, our world, and going to another; and The Lion, the Witch and the Wardrobe works in exactly the same way. So I wasn't being very original in using the basic idea.
What I did try to do was get the science right - though not for a scientific purpose: for a storytelling purpose. In my story, Lyra first becomes aware of the existence of other worlds when the witch's daemon tells her about them. What I was trying to do in that passage was not so much explain that other worlds exist - I was trying to convey to the reader the sense of awe and mystery that suddenly comes over Lyra. And when Will, in The Subtle Knife, goes through the mysterious window under the hornbeam trees to enter the city of Cittagazze, what I wanted the reader to feel was not a logical conviction but a sense of wonder. The purpose is different, you see.
But I did try to get it right. In the case of parallel worlds, I read as much as I could find about the matter; I went to a lecture by David Deutsch, a scientist who has done a great deal of research into the subject; and although I didn't understand very much, I hope I managed to absorb enough of the arguments to make the reader feel that the background was solid enough not to fall over when anyone leant against it. I think if you're convinced by one part of the story, you're a little more willing to believe the rest of it. I don't mean believe it's true, of course; we know it's not true. I mean believe that it works. My test was always: `I don't know very much about this, but I do know something, and if I read this in a novel, would it make me think that the writer knew at least as much as I did, and wasn't a complete fool?`
Well, many people much more scientifically learned than I am have read this trilogy, and found not too much, I hope, to quarrel with. Among them are the Gribbins, and the result of their reading is this book. When I first read it, I was enormously impressed by how clever I was. Then I read it again, and realised that if I'd got anything scientific right in the first place, it was because of the work of writers like them, who had explained these difficult ideas - and many others - with such clarity and skill.
Real scientists and science fans alike will find all kinds of things here to delight them. And if my story has been the cause of it, then no one will be more delighted than me.