For instance, he has what could have been a fascinating chapter that explores how the tuna steak bought at your local supermarket gets there. He goes on a fishing boat in the Maldives which catches the fish, not with a net but a line - supermarkets promise "line-caught" tuna, and that is true - and he visits the factory where the fish are gutted and chopped into the slabs that will, only a few hours later, appear for sale at supermarkets in Britain. But his discussion of the mechanics of the process stops just as it is getting interesting. There is nothing on the economics of supermarket products such as tuna. There is nothing about how the price of tuna is fixed or what percentage of the price is the result of transporting it from thousands of miles away. There is not even a pause for a moment's reflection about whether it is fair that the fishermen should be so poor and the people working in the supermarket, not to mention the managers and the buyers who have arranged the deal, so (relatively) rich.

The closest de Botton gets to the topic of the justice of the economic arrangements he has observed is when he meets a woman purchasing tuna at her local supermarket, and he "tells her about Karl Marx's theory of alienation as defined in his Economic and Philosophical Manuscripts of 1844". But that's it: the brandishing of Marx's name and the title of one of his books leads nowhere and does nothing at all except draw attention to the fact that de Botton can refer to Marx's tome - and the woman he is talking to can't.

That incident illustrates his tendency to reveal a sense of his own superiority. Perhaps that sense of superiority is justified, but it doesn't help him to understand what makes accountants and entrepreneurs (for example) tick. Despite several attempts not to, he can't conceal his contempt for the people who spend their lives thinking up names for biscuits and ways to market them. "The minders of the Ginger Nut and the Rich Tea, of the Jaffa Cake and the Moment," he claims disdainfully, "resembled a flock of patient, grave-faced courtiers ministering to the needs of a nursery of wilful emperors." You get the impression that he thinks the only difference between the two is that "the minders" of biscuits are involved in a much more futile task: the courtiers will at least deal with an adult emperor, who will be grand and noble, while those involved with the marketing of biscuits are doomed to lives of utter meaninglessness.