How to live well on nothing a year: 'Sacheverell Sitwell: Splendours and Miseries' - Sarah Bradford: Sinclair-Stevenson, 20 pounds - D J Taylor on Sacheverell Sitwell, a genuine narcissist with more charm than talent

IT WOULD be impossible ever to take the late Sacheverell Sitwell quite as seriously as he took himself. There are stage narcissists and there are genuine narcissists: the egotism on display in Sarah Bradford's long and engrossing biography is of the hard sort, and ominously consistent. 'I am, though I say it myself, about the cleverest young man of my age in the country,' its subject wrote in his twenties to the girl who was to become his wife, adding with delicate condescension, 'and I know you would like my companionship.' Interviewed shortly before his death in 1988 at the age of 91, he was asked to name his most treasured possession. 'Er, well . . . I was going to say myself.'

We have heard this note before, as it happens, heard it in Beaton's diaries, in the letters of Brian Howard and Stephen Tennant, and in half a dozen other Twenties falderals - the shrill, high note of the aesthetes determined to masquerade as geniuses whatever the evidence to the contrary. At least it can be said in Sacheverell Sitwell's defence that numbers of other people, principally members of his family, were keen to abet this delusion. As a poet, his sister Edith thought he was 'one of the greatest that our race has produced in the last 150 years'. The correspondence exchanged with his brother Osbert was, until they quarrelled about money, an object lesson in mutual flattery.

The Sitwell story, of course, has already passed into legend: the tragi-comic parents, Sir George and Lady Ida; the grim estate in Derbyshire; the endless pageant of self-love and recrimination. Sachie's interest lies in his ability - limited but distinct - to break free from the constricting embrace of brother and sister and 'the Gingers' (the junior Sitwells' nickname for their parents), largely by marrying at an early age but also by dissociating himself from his siblings' perennial pursuit of publicity. In his wife Georgia, whom he married in 1925, Sachie evidently found a boon companion, someone who understood him (rather too well, judging from the letter in which the bride- to-be complains that it is 'not my presence or affection that you love, but your isolated personal moments that have given you pleasure'), sympathised with the horror of being 40 ('both felt v sad about it') and shared his considerable capacity for enjoyment.

There followed a life of high-class tourism, interspersed with fallow periods on the Northamptonshire estate, much of it done on a shoestring. In fact a good title for this book would have been Thackeray's How to Live Well on Nothing a Year. Chronically hard-up until Sachie inherited the family money in the 1960s, the Sitwells led a heavily subsidised existence, their patrons including the Duke of Westminster, Siegfried Sassoon, Winifred Ellerman and a number of foreign governments apparently persuaded of the publicity value of Sachie's travel books. Children - there were two sons - seem to have been regarded as an occupational hazard. Three-year-old Francis nearly found himself abandoned in France with his nanny on the outbreak of war in September 1939.

Meanwhile, there were the books. Sachie began as a poet, later branching out into cultural rediscovery (Southern Baroque Art was a notable trailblazer in 1924) and, as the family star waned a little, travelogues. The poems, from which Sarah Bradford quotes extensively, are full of good lines, but the fact remains that they are all about the poet himself and the highly stylised aesthetic sensations he happens to have experienced. Bradford quotes a revealing passage in which he praises Edith's poetry for its 'degree of selection and separation from the dross of living'. It is precisely this quality that renders so much of his own work so distant and intangible. It is a wholly personal art, whose reference points are narrowly aesthetic. The way in which these preoccupations spilled over into Sachie's inner life can be glimpsed in a letter in which he mourns his mother's death: 'She had such a wonderful appearance. I long to see her hands, which were most beautiful.' However genuine her son's grief, somehow Lady Ida ends up resembling a china doll.

If Sacheverell Sitwell: Splendours and Miseries has a message, it is to confirm something we already knew: the complete redundancy of the art-for-art's-sake routine in the 20th century. Living the aesthetic life might just have been possible in the 1890s, aided by a private income and a resolute determination to shut your eyes to the outside world. In the age of Mussolini and Stalin it seemed wholly anachronistic. It is an interesting exercise, for example, to compare the Sitwell view of Marrakesh, recorded on a visit in 1938, with Orwell's essay written at almost exactly the same time. Sitwell sees the quack doctors' pharmacopia and medieval horrors. Orwell sees poverty, marching men - in other words the reality of life in a pre-war French colony, and its implications.

Sarah Bradford's method is recitative rather than analytic. Her early chapters suffer a little from the familiarity of the material, and it is only after the Second World War section, describing the family rows and Sachie's increasingly troublesome literary career, that she gets into her stride.

Several sections are no more than lists of tourist destinations and hospitality received. None the less, for anyone who wishes to understand a particular type of mind, busily at large amid the compost of the early 20th-century artistic life, and even now not wholly extinct, this is an essential document. What did his friends remember Sacheverell Sitwell for? It seems scarcely necessary to add that his most singular characteristic appears to have been his 'charm'.