A Night at the Majestic, by Richard Davenport-Hines

Richard Davenport-Hines, in this imaginative, gracefully written book, helps Marcel Proust fulfil his wish to preserve beyond death A La Recherche du Temps Perdu. He's an ideal friend for Proust: unobtrusive, affirmative, deeply respectful of his genius, patient and understanding of his contradictions, sexuality and neurasthenia.

The night of the title was 18 May 1922. An English couple, Violet and Sydney Schiff - rich, cultivated, Jewish and cosmopolitan - hosted a large supper party in a private dining room at the Majestic Hotel in Paris. It was to celebrate the first public performance that evening of Stravinsky's short ballet Le Renard by Diaghilev's Ballet Russes. To it Schiff invited the four men he most admired, all leading lights of modernism: Picasso, Stravinsky, Joyce and, above all, Proust.

It was an evening to which George Painter, in his fine linear biography of Proust, gave only a paragraph. Davenport-Hines makes it into a social and stylistic focus. Many of the guests were of the Faubourg Saint-Germain nobility who inspired Proust but on whom he closed the door so that he could write his great novel. By the time of the night at the Majestic, he had finished it.

It was his life's work. He was ill and ready to die. He arrived late, ate nothing, snubbed Joyce and suffered this brief severance from his hermetic dedication to work. Six months later, he was dead. With these two events Davenport-Hines devises a modernist structure with deference to classical unity: modernism had its roots in antiquity; its revolt was against Victorian repression, not Grecian liberty. Between them, he evaluates the issues that informed Proust's life and work.

Proust was "a man trying to maintain his soul alive". Davenport-Hines's skill is to give careful historical detail of his life, times and habits, without letting the weight of evidence bury this soul. Davenport-Hines sees A La Recherche du Temps Perdu as a theological work for a secular world, "a novel about the afterlife by someone who did not believe in Heaven or Hell".

Artistic immortality was Proust's goal. He was delighted when he won the Goncourt Prize in 1919. He wanted sales and praise, but his ambition was unworldly. He pursued not self-aggrandisement but truth of expression. His self-immolation was harsh. He had inherited money but his quarters were miserable. He ate next to nothing, shut the door to visitors and could not sleep though he swallowed opiates and barbiturates.

His workroom was his bedroom and sickroom. Through self-denial he pushed towards an aesthetic ideal, an unattainable prize. Towards the end he lived a death within life: he had his morning post steamed in disinfectant, thought his publisher was cheating him, and couldn't breathe because of asthma attacks.

Before he shut himself away, his life was more virile than its legend. He never missed a party, was quick to challenge to duels, financed a male brothel, gave extravagant tips to waiters, supported Dreyfus, sent food-parcels to the front in the First World War, and liked rough-trade sex. His mother was his great love. After her death he spoke of his ruined heart, but only then did he feel free to write A La Recherche. He needed to be unhappy and for lovers to be transient. He believed that romantic love yields disillusion and that art brings harmony and endures.

Proust believed his homosexuality made him more sensitive, and chose it as a secularised representation of the fall from grace. He knew that the choice was dangerous: a change in masculine dignity, a destruction of class barriers, an offence to family.

Sex for Proust was a matter of translation: of merged, confused and dissembled gender. Aged 20, answering a personality test, he replied to a question about the quality he most sought in a man: "feminine charms". The traits he preferred in women were "manly virtues and sincere camaraderie". In life he was fearful of being shamed because of his sexuality. His courage went into writing about it. He said he needed to be as exact about Baron Charlus's sexual adventures as about the Duchess de Guermantes' red shoes.

The night before he died, Proust dictated corrections to his proofs to Celeste. He edited his description of the death of the writer Bergotte: "they buried him but all through the night of mourning in lighted bookshop windows his books, arranged three by three, kept watch like angels with outstretched wings and seemed for him, who was no more, the symbol of his resurrection". Davenport-Hines offers an illuminated window to both Proust and his work.

Diana Souhami's 'Wild Girls' is published by Phoenix