According to Gladwell, we don't understand success. It's not just down to personal qualities - determination, hard work or talent. It's about arbitrary advantages such as parentage and patronage, or even when you were born (1930 was a good year for top New York lawyers, apparently). These hidden advantages, coupled with "extraordinary opportunities and cultural legacies", (speaking Chinese helps you become a better mathematician) are vital in determining how successful you are. Outliers - those exceptional individuals misleadingly described as geniuses (as, ironically, Gladwell himself is in the cover quotes) - are those who have been fortunate enough to have been in the right place at the right time and "who have had the strength and presence of mind" to make use of the opportunities. Of course, social historians have long understood that the key to explaining the significance of people and events is to place them in context. But in an age that idolises success and celebrity, Gladwell's compelling popularisation is timely and even important.

What do we get from Malcolm Gladwell, in return for all the adulation, multi-million-dollar advances and $80,000 speaker's fees? Listening to his detractors, you would think the answer is not very much, but that, of course, could be at least partly down to envy. There aren't that many journalists who have achieved millionaire status by doing nothing more than hopping from cafe to cafe with a book bag and laptop in tow.

Gladwell's previous two books, Tipping Point and Blink, sold nearly five million copies. They eloquently argued that social phenomena are spread in the same way as disease, and that our instinct can be more valid than our circumspection. On the back of them he became a global business and trends guru and the notion of a "tipping point" entered the modern lexicon.

His latest book, Outliers, which argues that success isn't primarily down to the individual, but to his or her context, has received mixed reviews. The New York Times called it "glib, poorly reasoned and thoroughly unconvincing". Germaine Greer said archly: "There is no answer to everything, and only a deluded male would spend his life trying to find it, brandishing the 'big idea' as a bookish version of male display". To be fair to Gladwell, he doesn't claim any great import; as he once put it in an interview, "I'm just trying to start a conversation . . . "

But where does his conversation lead? By revealing the otherwise hidden patterns behind outstanding achievements Gladwell certainly adds something to our received wisdom about why people succeed. His critics, though, are on to something. The book, ultimately, disappoints.

What Gladwell does undoubtedly do is present a series of interesting facts. He shows that how "good" you are at sports can depend hugely on which month you were born, as school leagues favour the bigger, ie older, children in each year. The success of corporate lawyers in New York is a tale of immigration, forefathers in the garment trade and anti-semitism. Even the uber success of Bill Gates and the Beatles is down more to chance and time of birth than raw talent, though, of course, Gladwell credits that, too, along with hard work and personality.

In Gates's case, says Gladwell, he happened to be born at the dawn of the PC age, in a place where he had easy access to usually prohibitively expensive mainframe computers. And the Beatles were booked to play hundreds of incredibly long gigs in Hamburg. As John Lennon said later, "We got better and got more confidence, we couldn't help it with all the experience playing all night long".

This idea, that the crucial factor in achieving the extraordinary is to be in circumstances that allow sustained development of innate talent - "a kind of accidental 'hot-housing'" provides the book with its best soundbite. Exceptional success, Gladwell suggests, comes with the 10,000-hour rule, which seems to be the common amount of practice required by all sorts of high achievers before they become real outliers.

Much of Gladwell's work, of course, is not original. He draws on little-known studies and academic sources, and this provides ammunition for his critics. One Nobel prize winner has admonished him for not sufficiently crediting the scientific work he draws upon. But that is churlish, surely. Gladwell does more than regurgitate. He first identifies and then takes hitherto obscure ideas, fills them out into a compelling narrative and adds plenty of anecdote and drama, before finding for them a mass and appreciative audience.

At the book's heart is the revelation that pure intelligence isn't enough. What great successes need is not the highest IQ but a high IQ, accompanied by other factors. What he's saying, in a message that should be seized on by anyone who regards themselves as progressive, is that it is society that provides the conditions for success, rather than the super-talented individual alone.

He tells the sad tale of Charles Langan, identified as a genius at an early age, who, because of a poor background and the inadequate social skills that resulted from it, has ended up drifting and disappointed. Gladwell contrasts him with the equally bright nuclear physicist Robert Oppenheimer, who reached the pinnacle of achievement because his family taught him the social skills necessary to work his way through numerous obstacles.

Like all Gladwell's stories, this is not conclusive, of course. Some poor kids develop amazing social skills, but each case is not meant to be definitive, just illustrative, and they do add up to a patchwork of evidence that convinces: we are not self-made. We are made, partly by ourselves, sure, but crucially, also by the times and society we live in.

The problem with this book, though, is that the end point isn't particularly startling. Unless you are an avowedly right-wing individualist, you probably already buy this core message. As the book unfolds there is a hunger for something deeper and more profound that never turns up.

Unlike Tipping Point and Blink, where Gladwell's weaving of facts and argument led to a seemingly new revelation, Outliers ends up being rather less than the sum of its parts. I guess that inadvertently tells us something else about success. Even outliers like Gladwell can sometimes manage only to be ordinary.

 Derek Draper is a psychotherapist and a Labour campaign adviser. To order Outliers for £15.99 with free UK p&p call Guardian book service on 0870 836 0875 or go to guardian.co.uk/bookshop

Malcolm Gladwell is a cerebral and jaunty writer, with an unusual gift for making the complex seem simple and for seeking common-sense explanations for many of the apparent mysteries, coincidences and problems of the everyday. He is also an intellectual opportunist, always on the look-out for a smart phrase or new fad with which to define and explain different social phenomena.

In his first book, The Tipping Point, he studied events such as crime waves and fashion trends and settled on an arresting metaphor to explain why they happen. 'Ideas and products and messages and behaviours spread just like viruses,' he wrote, suggesting that we contaminate and infect one another with preferences and recommendations, until we reach a 'tipping point', after which a social epidemic becomes contagious and crosses a threshold to reach saturation point. The tipping point: who does not now use this phrase to describe a moment of definitive transition? ('Tipping point' seems to have become this generation's 'paradigm shift', a phrase popularised by Thomas Kuhn in his 1962 book The Structure of Scientific Revolutions

The success of the book, which began as an article in the New Yorker, the magazine for which he works as a staff writer, propelled Gladwell into the realm of super-consultancy. He has since become a lauded pontificant and ideas progenitor on the international lecture circuit. He is the go-to man for a corporate business elite seeking to understand the way we live, think and consume today.

It helps that with his wild, unruly curls and wide-eyed gaze, Gladwell has the look of an übergeek. He seems to have absorbed one important lesson of the consumerist culture he deconstructs - that the image you project is paramount; in effect, he has made himself, superficially at least, into a brand. If you didn't know he was a writer and journalist, you wouldn't be surprised to hear that he was a leading operator at Microsoft or Google. As it is, he's a kind of literary Bill Gates, a guy so far ahead of the rest of the pack that you never quite know what he will do next.

What is an outlier? The word may not be a neologism but I have never heard anyone use it in conversation. According to one dictionary definition, an outlier is 'something that is situated away from or classed differently from a main or related body'. But Gladwell uses the word with more metaphorical flexibility. For him, an outlier is a truly exceptional individual who, in his or her field of expertise, is so superior that he defines his own category of success. Bill Gates is an outlier and so are Steve Jobs of Apple, Robert Oppenheimer and many others Gladwell speaks to or writes about as he seeks to offer a more complete understanding of success.

The trouble with the book is that Gladwell is ultimately engaged in a long argument with nobody but himself. Throughout, he defines his position against a floating, ubiquitous, omnipotent 'we'; a Greek chorus of predictable opposition and received opinion. 'There is something profoundly wrong with the way we look at success,' he writes. 'We cling to the idea that success is a simple function of individual merit and that the world in which we grow up and the rules we choose to write as a society don't matter at all.' And so he goes on.

These assumptions can be irritating, since who is this naive, unquestioning, plural intelligence identified as 'we'? Do we in wider society really believe that outstanding success, in whichever field, is achieved without extraordinary dedication, talent and fortuitous circumstance, as Gladwell would have it? Do we really take no account of the sociopolitical context into which someone was born and through which they emerged when we attempt to quantify outlandish achievement? Do we really believe that genius is simply born rather than formed? Gladwell wants his readers to take away from this book 'the idea that the values of the world we inhabit and the people we surround ourselves with have a profound effect on who we are'. But I don't know anyone who would dispute this.

The world for Gladwell is a text that he reads as closely as he can in seeking to decode and interpret it. He is adept at identifying underlying trends from which he extrapolates to form hypotheses, presenting them as if they were general laws of social behaviour. But his work has little philosophical rigour. He's not an epistemologist; his interest is in what we think, rather than in the how and why of knowledge itself.

There is also a certain one-dimensional Americanness at work: many of his examples and case studies are American and he spends rather too much time in New York, at one point even riffing at length about the founder of the literary agency that represents him. The book would have been more interesting if he'd roamed wider and travelled more, if it had been more internationalist in ambition and outlook.

However, it's still fun to follow Gladwell on his meandering intellectual journeys, even if the conclusions he arrives at here are so obviously self-evident as to be banal. Even when he is not at his best he is worth taking seriously. He has a lucid, aphoristic style. His case studies are well chosen, such as when he writes about the birth dates of elite ice hockey players and discovers a pattern: most are born in the first three months of the year. His range is wide, and he writes as well in Outliers about sport as he does about corporate law firms in New York or aviation. Little is beneath his notice.

One last thing, as Gladwell might say. There's perhaps another way of reading Outliers and that's as a quest for self-understanding, since the author himself is obviously an outlier. In seeking to find out more about how other people like him came to be who they are and to occupy the exalted positions they do, he's also indirectly seeking to learn more about himself, about how he came to be who he is: the smartest guy at the New Yorker, with the big ideas and the lucrative book deals.

 Jason Cowley is editor of the New Statesman. His book The Last Game: Love, Death and Football will be published in April 2009.