People have been staring into crystal balls for hundreds of years, sometimes with alarming accuracy. But usually they have been hugely, and entertainingly, wrong. Jonathan Margolis looks back at the history of futurology - and risks a few predictions of his own.

Buried deep in the stack at the Bodleian library in Oxford, from which it is exhumed on average once every 50 years, lies a forgotten early 18th-century book which is both fascinating and disappointing by turns. A rare volume - and deservedly so - Memoirs of the 20th Century: Being Original Letters of State under George VI was the first ever complete work of futurology.

Written around 1730 by a clergyman, Samuel Madden, it opens intriguingly enough, with a letter datelined Constantinople, Nov 3 1997, but sadly goes downhill from that point. Madden's 1997 is dominated by a George VI who is a mighty world emperor, but most of the book's 527 turgid pages are mired in contemporary, 18th-century concerns.

A couple of ideas suggest, none the less, that Madden really was thinking systematically about the future. He envisages the establishment of public granaries in all villages - pretty radical stuff, really - and even some prototype women's rights legislation. Thirty years later, another, more ambitious forward-looking book appeared, The Reign of George VI, 1900 to 1925, became a bestseller, and futurology was on its way.

This George was also a conquering hero, who tames the nations the anonymous author believed would be the miscreants of the early 20th century: France and Russia. The latter, 25,000 of whose troops sack Durham in a war of 1900, is seen as the world's second most powerful nation by this time, with America close behind. Not bad at all as predictions go.

The book wasn't all politics, either. It foresaw the legacy of the canal-building boom, which had just begun, and extrapolated that by 1900, a network of waterways would form a superhighway system, with the effect that "Villages grew into towns and towns became cities". Substitute trains for barges and you are looking at a decent stab at what today's multinationals call trend forecasting.

The Reign of George VI also envisages a king who hates modern architecture so much that he builds a new English capital city, called Stanley, in Rutland, which he fills with neo-classical buildings and surrounds by artificial mountains. Fanciful, perhaps, but strangely reminiscent of our own heir to the throne's ideal village, twee little Poundberry, in Dorset.

Futurologists tend not to get a great press. No wonder Samuel Goldwyn was moved to observe, "Never predict anything - especially the future", and Arthur C Clarke, whose 2001 has in so many ways failed to materialise, to comment wryly that, "The future isn't what it used to be."

Yet it is arguable that we are far too harsh in smug retrospect on those who attempt to peer round chronological corners. Naturally, when we try to envision the future, we always get trivialities such as the fashions and shape of cars wrong. Those sorts of visual cues are decided on a whim rather than a response to need. But most futurological predictions I have come across are almost spookily prescient in more significant respects. Take this extraordinary forecast, made in 1661-70 years before Samuel Madden - in a scientific treatise by the philosopher Joseph Glanvill, a clergyman and chaplain to Charles II, and a founder member of the Royal Society. "To them that come after us," Glanvill wrote, "It may be as ordinary to buy a pair of wings to fly to the remotest regions, as now a pair of boots to ride a journey; and to confer at the distance of the Indies by sympathetic conveyances, may be as usual in the future as by literary correspondence . . . I doubt not posterity will find many things that are now rumours verified into practical realities. It may be that, some ages hence, a voyage to the Southern tracts, yea possibly to the Moon, will not be more strange than one to America . . . the restoration of grey hairs to juvenility and the renewing of the exhausted marrow may at length be elicited without a miracle; and the turning of the now comparatively desert world into a paradise may not improbably be effected from late agriculture."

By the late-Victorian era, futurology was becoming really quite slick. Jules Verne described, for example, how musical recitals would by 2000 be sent down a wire from the artist to pianos around the world. Well, MP3 music on the internet hasn't worked out quite like that, but it's hardly dissimilar.

An American journalist, David Goodman Croly, writing in 1888 as Sir Oracle, predicted for the coming new century: "Women throughout the world will enjoy increased opportunities and privileges. Along with this new freedom will come social tolerance of sexual conduct formerly condoned only in men. In addition, because of the greater availability of jobs, more women will choose not to have children."

Twelve years later, another journalist, John Elfreth Watkins, having interviewed "the wisest and most careful men in our greatest institutions of science and learning" on behalf of The Ladies' Home Journal made a brilliant series of consumer predictions. The future, Watkins reported, would witness air-conditioning, international telephones, colour photography, frozen meals, medicine taken through skin patches, snowmobiles, the tapping of energy from wind, tides and sunlight - and out-of-season fruit.

Most amazing of all, perhaps, was Watkins's prophecy that, "Persons and things of all kinds will be brought within focus of cameras connected electrically with screens at opposite end of circuits, thousands of miles at a span."

John Maynard Keynes, also writing at the end of the 19th century, even prophesied e-commerce: "The inhabitant of London could order by telephone, sipping his morning tea in bed, the various products of the whole earth and reasonably expect their early delivery upon his doorstep; he could at the same moment and by the same means adventure his wealth in the natural resources and new enterprises of any quarter of the world, and share, without exertion or even trouble, in their prospective fruits and advantages." (Modern web shoppers will applaud Keynes's foresight, but regret that the "delivery upon the doorstep" part has yet to be sorted out.)

Oddly enough, the would-be seers who consistently get the future wrong are specialists in their field, the media's beloved "experts", whose futurological track record isn't nearly as good as that of those whose approach is that of the generalist (aka, inspired guessing).

The first expert futurologist was probably the Dorking vicar and demographer, Thomas Malthus, who in 1798 anonymously wrote a sensational pamphlet sounding the alarm on overpopulation. People had been complaining of overpopulation since Horace in 20BC, but Malthus was so convinced humanity would run out of space within a few years that he favoured effectively culling the working class, for which he was later derided by Karl Marx as "a miserable parson".

Two hundred years on, Malthus still has his fans, and the fashion for apocalyptic forecasting grows apace. In 1964, a British physicist, John Fremlin, speculated in New Scientist on population trends for the coming 1,000 years, and argued that by the middle of the 29th century, 60,000 trillion people, a million times today's population, would spend their lives lying prone and eating recycled human bodies in cubicles in 2,000 storey buildings spread across both land and what had been sea.

The apocalyptic certainty of choice today, of course, is global warming, which if its advocates are right, would be the profoundest ever future prediction. It is worth noting, however, that just a couple of decades ago, many of the same experts were confidently predicting global cooling , and a new ice age. "A new ice age must now stand alongside a nuclear war as a likely source of wholesale misery and death," said International Wildlife magazine in 1975. The next year, Science magazine reported that we were "heading for extensive northern hemisphere glaciation."

Even experts proferring non-apocalyptic futurology have been hugely and entertainingly wrong over the years. The Nobel prize winning physicist, Ernest Rutherford, the founder of nuclear physics, once declared that talk of nuclear power was "moonshine". Britain's astronomer royal, Sir Harold Spencer Jones, dismissed the idea of space flight as "bunk" in 1957 - a fortnight before the Soviet Union launched Sputnik 1.

And then there was Thomas J Watson, the former CEO of IBM, who never quite lived down a statement he made in the late 1940s: "I think there is a world market for maybe five computers." (Perhaps he really meant five computers per household.) No wonder that, in another of his dictums, Arthur C Clarke said that "when a distinguished but elderly scientist states that something is possible, he is almost certainly right, but when he states that something is impossible, he is very probably wrong."

So what predictions for the next century would I make, having interviewed dozens of both expert and generalist futurologists, and explored the pitfalls and triumphs of past futurology? Well, I can't see the old favourite, household robots, ever taking off - another massive instruction book to read, another machine to drive us mad with software seizures.

It is hard, similarly, to see artificial, computer intelligence being much of a starter, although it's promised for as early as 2015. Even if it could be achieved (which human brain experts are very sceptical of, pointing out that our most powerful computer currently has the intellect of an earthworm) there would, surely, be no market for computers which, when given a boring job, told you to do it your damned self.

We like computers, surely, for their artificial stupidity . And if they get too clever, won't they soon start complaining of cruelty? (You laugh, but cruelty to computers is said to be close to becoming a social issue, and is already being discussed by acade mics specialising in human rights.)

Genetic engineering will, I strongly suspect, also fail to deliver a fraction of what its advocates promise. There will be endless cases reported in the press around 2025 of people who supposedly had the "criminal gene" edited out of their DNA, and subsequently been convicted of car theft. Likewise, parents who paid to have the "gay gene" excised (probably illegally) from their children's make-up and ended up disappointed by the result will be locked in litigation with the clinics who did the genetic work.

Time travel, I can't see happening either. It took the great Stephen Hawking to point out the obvious objection - that if it were possible, surely we would have seen tourists from the future by now? Quantum teleportation a la Star Trek is said to be a possibility, however. But whether a teleported human will arrive at his destination complete with his mind and memory intact will be an interesting one to watch.

Medical advances, meanwhile, may well soon make death a lifestyle option rather than an inevitability, and this could have extraordinary repercussions. If you take the view, for example, that religion has only existed for the past few thousand years because of our fear of death, could the prospect of eternal life finally destroy religion once and for all? And could that, in turn, lead to an overwhelmingly amoral society?

Space travel - and the eventual colonisation of other planets is probably inevitable if we all live for hundreds of years - may throw up some interesting conundrums too. For what will be tax position of the colonists? The first generation living on another planet may feel allegiance to the country that paid for their trip and the building of their base. But thereafter, it seems probable that Mars-born humans who only know Earth as a dot in the night sky, might resist attempts to tax them. Maybe there will be a space repeat of the 1773 Boston tea party?

One thing is certain for the future. Just as we fervently believe we are living in a special time, and are a special generation witnessing a huge turning point in human affairs - so will our grandchildren and their grandchildren. Every generation thinks the same, and they're always just a little bit wrong.

 A Brief History of Tomorrow: The Future, Past and Present, by Jonathan Margolis, is published by Bloomsbury, priced £14.99