A decade ago, Planet Hawking came into view. Where will the next science boom come from? John Gribbin investigates
A Brief History of Time: tenth anniversary commemorative edition

by Stephen Hawking

Bantam Press, pounds 15

Life's Other Secret

by Ian Stewart

Allen Lane, pounds 20

Ten years ago, popular science publishing was a backwater. The few books that were published got little shelf space in the shops, and window displays of science titles were unheard of. If I found a single copy of one of my books in a high-street shop, it was a cause for rejoicing and a celebratory cup of coffee.

Now, things are different. Science books get reviewed; the authors appear on Start the Week, and a profusion of titles fills an impressive stretch of shelving in the bookstores. Today, when I go into one of those shops, I am disappointed if there are lower than half a dozen of my own books there to be rearranged into more prominent positions, while I hide the books by Paul Davies and my other competitors in inconspicuous corners of the display. So what changed, and why?

The glib answer is the publication of Stephen Hawking's epic bestseller, A Brief History of Time, exactly ten years ago this week. The event has been marked by the appearance of a new, updated version of the book, labelled a "commemorative edition". Among the things being commemorated is the fact that the original edition has sold one copy for every 750 people alive on Earth today, in spite of (or because of?) being a notoriously difficult read for anyone without a degree in physics.

The new edition is mildly disappointing, and contains very little new material except for Hawking's thoughts on time travel, which do not in themselves justify the pounds 15 cost. If it were a conventional book, it would be hard to see much of a market for it. But, of course, it is not a conventional book, and just as in the Middle Ages people revered enough pieces of the True Cross to build a battleship, so today many of the millions who bought the original Brief History may want to have this version as well. It is as if by owning it they gain some mystic communion with the gods of science. And there is also, no doubt, the thought in the back of the publisher's mind of the 749 potential additional customers for every copy of the book sold.

The "Hawking effect" undoubtedly contributed to the boom in science publishing, as other publishers leaped aboard the bandwagon, seeking out scientists who could write, and bookstores cleared space on their shelves for the titles.

In many ways, this became a self-fulfilling boom. The fact that the books were publicised and available in the shops, instead of only by special order, meant that more were sold, which encouraged publishers, writers and bookshops to generate even more product and publicity. The timing was also perfect for the revolution in bookselling in Britain, which has brought a spread of bookshops into the high streets, with bigger and brighter stores competing with one another for the passing trade.

And there has been a more modest, but still significant, contribution to the publicity machine from the Science Book Prize, now sponsored by Rhone-Poulenc, which was serendipitously born in the same year, 1988. (It is interesting to note that the award never went to Hawking's book.)

The Science Book Prize has generated increasing amounts of publicity over the years (and given increasing boosts to the sales of shortlisted books), but it has also highlighted some curiosities about the whole science publishing phenomenon. First, to the chagrin of professional writers (the ones who make a living solely by writing about science), it tends to focus on books by active scientists, to whom writing is a lucrative hobby - the likes of Richard Dawkins, Steve Jones and Stephen Jay Gould. (In a desperate attempt to ingratiate myself, I have recently gone back to academic research, but so far the judges haven't taken the hint.) Second, it appears to have a bias towards biological titles - by people such as Richard Dawkins, Steve Jones and Stephen Jay Gould.

Until very recently, this slant - in addition to Hawking's own success - was an accurate reflection of the public interest in science. Books about the the big questions - the meaning of life, or the origin of the Universe - did best. The great mystery was why books on mathematics were not being published in large numbers, and failed to sell very well when they did appear.

Then came another phenomenon, striking as much out of the blue as the success of Hawking's book. Last year's thing was, of course, Fermat's Last Theorem. Simon Singh's book naturally appeared on the shortlist for the 1998 prize, alongside four purely biological books and one that discusses both quantum physics and life. But it failed to win. In keeping with the tradition of the Science Book Prize, but to the great disappointment of most observers, the judges settled for the soft option of giving the prize to Jared Diamond for Guns, Germs and Steel. His book, about the environmental forces that shape cultural development, may make arts graduates feel comfortable, but it is sad to see a rare opportunity to honour a good maths book pass by.

Thanks to Fermat, mathematical titles have been appearing like weeds in publishers' catalogues. this year. The person who stands to benefit most from this new development was already on the job before Singh's book hit the bestseller lists. Ian Stewart, Professor of Mathematics at Warwick University, has been writing excellent popular books about his subject for well over ten years, but never achieving the sales of a Dawkins, Jones or Gould. Being nobody's fool, when he had the opportunity to take a sabbatical year, he used it to find out about biology, and to write a book describing the way mathematics underpins the workings of the living world.

Life's Other Secret is a masterly account of the workings of life from the perspective of the mathematician, making an often familiar story seem new and intriguing. The first secret of life, according to Stewart, is the structure of DNA, the life molecule. Few would disagree with him.

Mathematics may be the other secret of life, but only in the sense that it is the other secret of everything. It underpins such diverse topics of investigation as the Big Bang, the structure of the atom, and economics. But I'm inclined to agree with Stewart that "The Other Secret of the Atomic Nucleus" would not make a sexy title for a bestseller, and that getting the word "life" into the title of a mathematics book is a smart move.

It must puzzle Stewart a little, though, to see the way that maths has made a popular breakthrough without him, while he was beavering away on this masterwork. But it is hard to see how it will fail to become a bestseller, and I am sure it will be shortlisted by the judges of next year's award.

So where do we go from here? Can the boom continue for another ten years? Where are the gaps in the market that academics as smart as Stewart should exploit in the future?

The big surprise to me is that there are no books about the Earth itself breaking into this market. Geology is perceived as old hat (it was the cosmology of the 19th century), and people are tired of doomsaying about global warming, ozone depletion and the like. But the present understanding of geophysics - how our planet works - is as dramatic as the story of the Big Bang. It is now a timely tale to tell, with data and images coming in from other worlds (notably Mars and the moons of Jupiter) which provide a comparison and contrast with our own planet.

So anyone tempted to try an Ian Stewart for next year should, in my view, look at planetary science and geology. But I suspect that writers taking my advice will be startled to see another surprise roaring into the charts, just as the publishing world was taken unawares by A Brief History of Time, and more recently by Longitude and Fermat's Last Theorem. That is why the whole science publishing boom is so intriguing, and such a delight. As long as it stays unpredictable, anything might appeal to the book-buying public. We are all in with a chance of following in Stephen Hawking's footsteps.

Dr John Gribbin is a Visiting Fellow in Astronomy at the University of Sussex. His biography of Stephen Hawking, co-written with Michael White, is now published by Penguin