Want to give up smoking? Can't get a boyfriend? Can't get a job running a powerful new world economy? Want to invade a small Middle-Eastern country but unsure if the planets are suitably aligned? Concerned about what the placement of plants in your living room is doing to your chakras?

Then don't be proud. Seek help. Have a makeover. Get yourself a guru. Book a feng shui consultation. See your astrologist. Organise a rebirthing ceremony for yourself and the wife in the middle of the Mexican jungle.Call 1850-SUCKER and find out how to be a better person.

The moder n world, it seems, is divided into those who do (and boy, do they - the average self-help consumer owns 12 different titles in the genre), and those who'd rather curl up at home with a bout of syphilis than the latest title from Deepak Chopra.

But even if the words `read this - it'll change your life' provoke in you a similar reaction to `Don't worry, it's not loaded', the selfhelp industry is one you can't ignore.

At a time when publishing in general is in a slump, sales of titles like the Seven Habits of Highly Effective People, the Five Keys to Wealth and Happiness or the Eight Ways to Enrich Your Marriage (numbered list s seem to figure large) are booming.

In Britain last year, sales of selfhelp - or `mind, body and spirit' as it's sometimes more grandly known - literature generated €55.6 million. The year before that, it made €48 million; the year before, €44 million.

Imagine how much poorer our lives would be without life gurus and self-help authors to show us the way.

Who knows,we might never have thought of putting civil servants in coloured hard hats to help them make tough decisions; we could have gone our whole lives without once pondering how Confucius or Elizabeth I would have behaved if they'd run Enron, or guessed how a frog would have acted if you dropped it into a pot of boiling water (it jumps out, apparently). And we'd not - perish the thought - have had the foggiest that our souls needed chicken soup.

But smirk though we might - and it would take a truckload of Botox not to - the growth in what Francis Wheen calls "Statements of the Obvious Inc" is symptomatic of something far more troublesome.

Namely, the fact that reason has upped and left the building.

InWheen's new book,How Mumbo-Jumbo Conquered the World: A Short History of Modern Delusions, he quotes philosopher Roger Scruton: "Reason is now on the retreat, both as an ideal and as a reality."

Because, sometime dur ing the 1980s, after the advent of Margaret Thatcher in Britain, the space that had been so recently colonised by meaningful politics, history, progress and reason wa s t ake n ove r, Wheen believes, by cults, quackery, gurus, irrational panics, moral confusion and an epidemic of shameless - but highly lucrative - mumbo-jumbo.

The growth in the self-help industry is only its most obvious manifestation.While millions of people around the world have been inspired by such unadulterated tosh as "You must have resilience to overcome personal misfortunes" (thank you,Wess Roberts) and "You are inherently perfect" (cheers to you, Deepak Chopra), the gurus are whooping and cheering all the way to the bank. Of course, if they offered nothing but Hallmark-card ruminations and Christmas cracker-wisdom, the appeal of these books would be limited, as Wheen insightfully puts it, "to a few simpletons".

But they season their fauxnaivety with enough faux-sophistication - courtesy of such neologistic, and now sadly familiar, jargon as `benchmarking', `downsizing' and `re-engineering' - to convince readers that there is a scientific rigour to it all.

And they are convinced, in their legions - from Demi Moore, who has announced her intention to follow Chopra's wisdom and live to 130, to Donna Karan,who was replaced in 1997 as chief executive of her own company, after investors decided that consulting the crystals was not necessarily the most effective way to run a listed company.

In 1994, reeling from the Democrats' defeat in congressional elections, Hillary Clinton, that otherwise apparently sane woman, invited five professional feelgooders to spend the weekend with her and Bill. They included Stephen Covey, author of the Seven Habits of Highly Succ essful People and Jean Houston, a self-styled "sacred psychologist".

As the weekend wore on, it was increasingly dominated by Hillary's own problems.

Houston, who felt that "being Hillary Clinton was like being Mozart with his hands cut off", informed the First Lady that she was "carrying the burden of 5,000 years of history when women were subservient . . . probably more than virtually any woman in human history - apart from Joan of Arc".

Houston and the latter-day Joan conducted seances in which they consulted Clinton's `spiritual archetypes', Eleanor Roosevelt and Mahatma Gandhi.

When it came out, the reaction of Republicans to Wackygate was uncharacteristically muted. But hadn't their very own Ronald Reagan made a point of clearing every major move he made in office with a San Francisco astrologer?

Unfortunately, such highlevel quackery has not been confined to the far side of the Atlantic. Even the "no-nonsense Margaret Thatcher" (whose insistence on a return to `Victorian values' Wheen pinpoints as a starting point for this anti-revolution) was a devotee of electrical baths and Ayurveda therapies, he notes.

The more recent inhabitants of Downing Street make Thatcher's dalliance with the forces of mumbo-jumbo look like child's play.

Cherie Blair has invited a feng-shui expert to rearrange the furniture at the prime ministerial home and in times of difficulty is known to wear a `magic pendant' that surrounds its wearer with a `cocoon of energy' to ward off evil forces.

Labour supporters used to dismiss her wackier proclivities as an eccentricity for which her husband had, at best, a benign tolerance.

It became a little more difficult to spin this line after it was discovered that the Blairs had undergone a rebirthing ceremony together while on holiday in the Mexican jungle in 2001.

Wheen quotes from The Times' account of the event at some length: "Herb-infused water was thrown over heated lava rocks, to create a cleansing sweat and balance the Blairs' `energy flow'.

"Aguilar [Nancy, their spiritual guide] chanted Mayan songs, told the Blairs to imagine that they could see animals in the stream, and explained what such visions meant.

"They were told the Te-mazcal was like the womb, and those participating in the ritual most confront their hopes and fears before `rebirth'.

"The Blairs were offered watermelon and papaya, then told to smear what they did not eat over each other's bodies, along with mud.

"The prime minister, on holiday just a month before the September 11 attacks, is understood to have made a wish for world peace.

"Before leaving, the Blairs were told to scream out loud to signify the pain of rebirth. They walked hand in hand down to the beach to swim in the sea."

World leaders' love of mumbo-jumbo is not, it seems, a peculiarly modern phenomenon.

The former head of the British defence establishment between 1971 and 1974 and chairman of Nato's military committee from 1974 until 1977, Lord Hill-Norton, contributed a preface toTimothy Good's 1991 book, Alien Liaison.

Good claimed to have uncovered evidence that several "alien spacecraft" had been captured by the US government, which was test-flying them at "a super-secret base in the Nevada desert". So what did Hill-Norton say in his preface - "What you are about to read is complete twaddle"? Not a bit of it.

Describing Good as an "honest and reliable" investigator, he said the allegations were "impossible, certainly for me to dismiss, unless they were publicly disproved".

But, someone ventured, didn't he think that he might have heard about it? "You'd think I would have known," he conceded incredulously. "But I hadn't the faintest bloody idea."

Good noted that the coverup was classified at "38 levels above top secret." (Which itself calls for the question, who did know about it - God and Saint Peter?)

As our collective grip on reality becomes increasingly precarious, even ufologists, who count Prince Philip amongst their number, are no longer an endangered species (though they might beg to differ with that assessment).

According to one opinion poll conducted in the US in the 1990s, some 2 per cent of Americans said that they had been kidnapped by extra-terrestrials at least once. That translates to some 3.7 million abductions - or "an air traffic control nightmare", as John Leonard commented acerbically in the Nation.

Every aspect of modern life has been infected by this exodus of reason and common sense, even - or more correctly, especially - academia.

Wheen, whom the Guardian has called "one of the most playful and effervescent lefty commentators around", is positively vitriolic about the postmodern academic culture that has proudly turned its back on enlightenment values.

In their place, it peddles the view that there are no certainties or realities, that everything from history to quantum physics is merely a perception, a text subject to interpretation.

Wheen quotes academic and writer Terry Eagleton, who notes that, for a school so fond of irony, postmodernism has failed to notice the most glaring irony of all.

"In pulling the rug out from under the certainties of its political opponents, this postmodern culture has often enough pulled it out from under itself too, leaving itself with no more reason why we should resist fascism than the feebly pragmatic plea that fascism is not the way we do things in Sussex or Sacramento."

Eagleton went on to say that so wedded is postmodernism to style and pleasure at the expense of content that it "often churns out texts that might have been composed by, as well as on, a computer".

A year after these remarks were published, Australian academic Andrew Bulhak decided to see if this was indeed the case. In 1996 he designed a computer program to write postmodernist essays.

Visit his postmodernismgenerator (www.elsewhere.org/cgi-bin/postmodern/) and you can, in a matter of seconds, create your own apparently serious academic paper, complete with footnotes and the essential babbling impenetrability, on The Precapitalist Paradigm of Expression in the Works of Gibson, or Cultural Discourse in theWorks of Joyce.

"The essay you have just read is completely meaningless," concludes the final footnote proudly.

Professor Alan Sokal of New York University took this debate one step further, and had "an article liberally salted with nonsense" and obliquely entitled Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity, published in the leading US journal Social Texts.

"While my method was satirical, my motivation is utterly serious. What concerns me is the proliferation, not just of nonsense and sloppy thinking per se,but of a particular kind of nonsense and sloppy thinking: one that denies the existence of objective realities," Sokal explained.

Sloppy thinking, sensationalism for its own sake and the denial of objective realities are, it becomes increasingly clear in Wheen's Mumbo-Jumbo, the defining cultural themes of the past 25 years.

While his work alternates between hilarious insights into the contemporary obsession with media and celebrity, and serious issues of academic debate, it comes back again and again to the same question: when did everything stop making sense?

The life and death of Diana Spencer, he argues, perfectly illustrate our willingness to allow critical judgement to be overshadowed by the lustre of celebrity.

When she became engaged to Prince Charles in 1981, he writes, Diana was "just another dim, roundfaced Sloaney girl of the kind you could see on almost every street in Pimlico, clad in the unprepossessing uniform that prompted some observers to liken her, cruelly but accurately, to a stewardess from Air Bulgaria.

"By the time of her funeral sixteen years later, she was routinely if ludicrously described as one of the most beautiful women in the world, and the most saintly."

All that happened in between, he attests, was that she spoke through "smudgily kohl-rimmed eyes" of her betrayal at the hands of the man she adored and the prince she married, and she died in a car crash in Paris.

But anyone who digressed from the popular perception - as Professor A nthony O'Hear found when he tentatively suggested that the reaction to her death lacked a sense of proportion - was regarded as a public enemy.

Even Tony Blair came out to condemn O'Hear, dismissing him as "an old-fashioned snob",while the Dáily Mirror rather more lyrically called him "a rat-faced little loser".

As yet another example of our increasingly tenuous relationsh ip with reality, Wheen cites the debate over the Bible Code book, published in 1997 and serialised in the Dáily Mail newspaper.

TV journalist Michael Drosnin claimed that he had discovered a computer program written by an Israeli scientist that decoded the hidden text in the Bible, predicting "every event in world history".

Drosnin was unimpressed by claims that this method of "equidistant letter spacing" could be applied to any large slab of text with similar results. "When my critics find a message about the assassination of a prime minister encrypted in Moby Dick, I'll believe them," he told Newsweek.

Brendan McKay, of the Australian National University took up the challenge. Subjecting Melville's novel to the Drosnin technique, he elicited the phrase "I GANDHI THE BLOODY DEED" - quite obviously, a chilling reference to the assassination of Indira Gandhi.

Ironically, the final extract of the book was withheld from the Dáily Mail due to space constraints. The divine author of the Bible, who had allegedly foreseen all the major events in history, had failed to predict the death in a car crash of Diana and Dodi Fayed on Sunday August 31, 1997 - and the effect it would have on the book's lucrative serialisation deal.

How Mumbo-Jumbo Conquered the World: A Short History of Modern Delusions by Francis Wheen is published by 4th Estate