Bill Bryson: Life, the universe and everything

He is every Briton's favourite American, and his laconic travel books have made him a fixture on the bestseller lists. But why did Bill Bryson decide that his new project should be about science, of all things? He explains that, and why he's moving back to Britain, to John Walsh

Bill Bryson sits on stage in the biggest tent at the Hay Festival, looking apprehensive. It's a boiling afternoon and the 1,200 Bryson fans who are cramming the marquee for the festival's climactic event have racked the temperature up to the mid-40s. In his nondescript cotton trousers, sensible jacket and straggly beard, Bill does not look a man happily attuned to hot climates. He looks like a librarian who has strayed into a hot jungle clearing, to be faced by 1,200 savages wielding blowpipes.

For the great travel writer has done something that his fans may find hard to forgive. He has published a book with no travel writing in it - no droll encounters with Blackpool landladies, no satirical riffs on the absurdity of cricket in Australia, no epic rambles with ill-equipped partners in America. Even worse, his new book is about science - hard science, protons, neutrons, cosmology, quantum mechanics, difficult stuff that his readers would sooner disembowel themselves than read about.

Bryson has just spent 45 minutes on stage talking scientific theory. Now, it's their turn. Will they abuse him? Will they say: "How can you let us down like this?" And: "What do you know about science?" Will they ask him something that he doesn't know about Heisenberg's Uncertainty Principle? Will they ask: "Mr Bryson, what is the meaning of life?"

The first questioner joshingly enquires about the health and whereabouts of Stephen Katz, Bryson's hapless sidekick in A Walk in the Woods. Next, a woman fan reminds him of an episode in his book about England, and, twinkling fit to bust, asks: "Have you worked out what a counterpane is for yet?" A third asks him to read out a passage from his book on Australia, as if inviting him to massage her spine. The fourth goes straight over the top. "I hear you're doing us the honour of coming back to live in England, " she gushes. "When will that be?" The audience murmurs approvingly, as if they were all, individually, thinking of inviting him round for tea at the earliest opportunity.

Goodness, how they love him, quarks and protons notwithstanding. How the British reading public loves Bill Bryson, their favourite deracinated Yank. In their heads, he's still the baffled Midwesterner, far from home and bewildered by English social conventions, the man who makes quietly caustic observations about our weather (looking at the typical English sky "makes you feel as if you're living in a Tupperware container"), and our national sport ("[in a cricket match] the number of calories burned by the spectators is the same as that burned by the players - or more, if the spectators are slightly restless"), even though Bryson departed from his adopted home of Yorkshire, to return to the States, five years ago.

This diffident, pipe-smoking, ruminative scholar became a National Sweetheart - someone who, like Vera Lynn, Noël Coward and the Queen Mother, makes the British people feel happier about themselves - when his Notes from a Small Island was published in 1995. In it, Bryson offered his adoptive countrymen a beguiling picture of themselves as a race of quirky, slightly truculent eccentrics, endearingly fond of chocolate biscuits, Gardeners' Question Time, and place-names such as Tooting Bec and Scratchy Bottom. It catapulted him to writer stardom. All his other travel books (most recently, A Walk in the Woods and Down Under) have whizzed to the top of the bestseller lists on publication. And now, rather amazingly, so has A Short History of Nearly Everything, the first hard-science chart-topper since its near-namesake, A Brief History of Time.

Was he relieved? "Not especially," he replies. "But I'll be relieved if my next book goes to No 1. There's a real danger of losing all my readers. I'm afraid people will go and buy this one because it's the new book by me and they'll think, 'Oh, Dad likes all his books'. But if Dad doesn't like this one, maybe no one will buy the next..."

Mr Bryson is a champion worrier. His hairy, bespectacled face is often creased with nameless concerns, as he wrestles with issues of incomprehension, luck, God, genius, poverty, tribalism, and the problem of describing nothingness. His new book starts with a lot of wondering - not just about the nature of the universe, but about the glibness with which scientists explained it at school.

"I was no good at physics and chemistry as a child," he says. "I've always been lost by those subjects. I didn't understand them. Even now, even having done this book, if you put me on a basic physics course at university, I'd be lost by the third week, I'd have to go to my son to get help with my homework." He was led to the science project by dabbling in natural history, "trying to understand how mountains are born when I was writing about the Appalachian Trail; trying to understand why Australia is so geologically and atmospherically distinct, and why it feels so old". At the same time, he'd found himself reflecting that, "I didn't know the first thing about the only planet I was ever going to live on. I had no idea, for example, why the oceans were salty but the Great Lakes weren't."

He'd wanted a break from travel writing, he wanted a new project, he'd made Mrs Bryson "a vow that I'd do something that wouldn't take me away from home so much". And gradually, it dawned on him that the biggest subject in the world - the subject of the world - was staring him in the face. "The idea that once there was Nothing - and now there's Us. How did we get from that to this? It didn't really occur to me what a preposterously big subject I was taking on. Though it became evident pretty quickly..."

His vow to his wife suffered a dent as he realised that he couldn't stay at home and regurgitate other science books. "I thought, no, I gotta spend a lot of time talking to scientists. At first, I had some pointless interviews with people when I wasn't near ready to ask questions. You just cannot go up to a particle physicist and say, 'Sorry, but what is a molecule?'."

He persevered, and the result is 30 chapters of slightly awestruck potted science - cosmology, palaeontology, evolution, cells, oceans, forests, the birth of self-creating life, the rise of man. Sensibly, Bryson leavens the jaw-dropping statistics and atomic physics with some droll stories of scientific endeavour from the last 300 years. Such as the astronomer Percival Lowell, who believed that Mars was covered with water-ferrying canals built by industrious Martians; few sought to disagree with him because he was, after all, endowing the expensive Lowell Observatory (which discovered Pluto in 1930).

Most discoveries, Bryson notes, were the result, not of patient application, but of luck or serendipity. One of his favourites was that of Reginald Sprigg, an Australian geologist, "who discovered Precambrian life when it wasn't known to exist, because he was out in the south-Australian desert one day, eating his lunch. He idly turned over a rock with his foot and saw there were fossils that weren't supposed to be there. Now, he's in all the books. There must be thousands of geologists of his generation who sat having lunch in the open and never saw a thing in their lives except some damned trilobite."

Bryson is at his most animated when talking about things that he's discovered in his research - the scary flesh-eating bacteria; the bdelloid rotifers that can switch off their metabolisms and blithely survive any extremes of temperature; the statistics about the earth's crust and the edge of the universe. He loves making imaginative leaps across time and elements: he points out that the static fizz on your TV set is a tiny distant echo of the Big Bang; and that the scent of Chanel No 5 is the distillate of a giant squid that's spent some time in a sperm whale's stomach. And he admits how hard it was to find the right words to evoke the Big Bang. "I worked very hard on it, but, essentially, there isn't a way to describe how something smaller than microscopic could expand at incredible speed and become the whole universe in three minutes. Describe it? You can't even imagine it."

His book is a journey of understanding, that takes him to the frontiers of scientific research, where the particle physicists roam. It's around here that the master of explanation admits defeat. "I think physics has reached a point," he says, "around the area of string theory, where it is absolutely ungraspable. A point where it's just not possible for one non-scientist to convey things meaningfully to another. It's like being able to converse only if you both speak Italian. Either you speak physics or you leave it alone and accept that there are some regions of science so arcane we can't deal with them." Did it make him frustrated? "I came away with a deeper admiration for people who do these things," he said. "Now I understand why I don't understand physics better than I did before."

Since Bryson is a non-believer who never mentions the Book of Genesis, is he likely to run into trouble with the Creationist lobby? "Yes, without question. But by the end of the book, the feeling I came away with is that science isn't incompatible with religion. When you ask questions such as, 'Why the Big Bang?' 'Why did the universe suddenly burst into flower and expand the way it did?' 'What inspired the moment of Creation?', then God is as good an explanation as any. In fact, conventional scientific belief - that all this unfolded with such elegant majesty - is a much more impressive explanation than saying, 'Oh, God did it all 10,000 years ago, and all the other stuff has been concocted to cloud the issue'."

The last three years have clearly been a labour of love for Bryson, and he's keen to get back to what he's best known for - travel writing. "It was pretty easy to sell my publishers the science idea, but if I went to them now and said, 'I want to do Volume II', they'd probably beg me to do something else." How about, I suggest, a book on philosophy? I think we'd all benefit from reading Bryson on Kant, Bryson on Wittgenstein, Bryson on Spinoza... "No thanks," he says. "I will write about Spinoza only if it's a... a Spanish cocktail."

Having covered America, Europe and Australia, he has yet to write about Africa and Asia. Are they on a future itinerary? Amazingly, he has never been to India, but, "I fully expect to be doing it in the next couple of years". He has a problem with writing about the Third World, however. "I can't find much humour in street beggars and people sleeping under bridges. I have a real problem with that. You have to be so much more careful." He recently made his first trip to "real Africa, as distinct from the Seychelles and South Africa, which are a special case", when he visited Kenya as the guest of Care International, to look at their projects in the slums of Kabira, outside Nairobi. "You have to be conducted through it, because it is too dangerous otherwise. It goes on for miles, and the smell and the squalor and the density of life going on there... and there comes a point after an hour and a half when you think, 'Don't take me any deeper into this, I just can't assimilate it'. And you realise, this is just one slum out of dozens in Nairobi. The scale of the problem is overwhelming."

With what seems like slightly childish idealism, he refuses to be negative about it. "I do think that, with 15 or 20 years of good government, stable government, and help from the outside world, you could turn the place around. It wouldn't suddenly be Paris or London, but it would be much better than it is. What they need is focus and responsibility and help, a government that's not corrupt, and an outside world that's helping them on."

Blimey. Is there a danger that the genial Bryson, the wide-eyed traveller and droll sceptic, is being turned into a diplomat, a goodwill ambassador, a political engagé? He shakes his head. "I'll always be extremely naive as far as politics is concerned. You can pull the wool right over my eyes. I think I'll always be well-meaning and tempted into simplistic answers. Politics is not a place where I should go, it's not a territory where I can make a difference as a writer. But I can help a group such as Care to raise its profile and generate funds. If you really want to appreciate a place such as Africa, you need Paul Theroux, someone more sophisticated than I am. I'm happy to leave it to him. Making jokes is what I do."

Calculated self-effacement is what he does, too. Mr Bryson is not a natural joker. His strength has always been his irresistible yoking together of enthusiasm, wonderment and laconic humour. But in many of his books you can detect a desire to do more than skate across the surface of things, places, people - to flex his considerable intelligence, to test his powers of understanding. Hence, I suspect, A Short History of Nearly Everything.

And now (hurrah!), he and his family are coming back to live in England. They've bought a house, not in Yorkshire this time, but in Norfolk. "The reason we're moving there isn't the geographical area, it's because we really like the house. These days, you go online and say, show me all the houses you've got in this price range, and you see what comes up."

The Bryson price range must, I observe, be pretty stratospheric these days. Is he buying an 18th-century manor house, the maison de choix of retired rock stars? "No, no," says Bryson, laughing. "I'm not in that league. You don't get that rich by writing books. I'm very, very comfortably off, I don't deny it. But did you see the obituaries of Mickie Most? They said he was worth £50m. You don't get that kind of money from books, unless you're J K Rowling or Stephen King."

So, no stables then, full of thoroughbred racehorses? "God, no," yelps Bryson. "It has five chickens. We're inheriting five chickens..." Even as he says the words, you can see a future chapter on Poultry Husbandry forming in Mr Bryson's ever-expanding brain.