Roll up for the masterful mystery tour

Ruth Prawer Jhabvala has written her best novel since Heat and Dust. By Euan Cameron; Shards of Memory by Ruth Prawer Jhabvala John Murray, pounds 15.99

Who exactly was "the Master", the mysterious, ageless guru figure with the hooded, slanted, pewter-coloured eyes, whose all-pervasive influence plays such a significant role in the lives of the characters of Ruth Prawer Jhabvala's new novel? Some said he was Nasir Sallah, son of a carpet seller from Tabriz, a spy working in those debatable mountain frontiers that lie between India and Russia; others that he was the son of a prosperous horse-dealer who had been initiated into secret doctrines in a Tibetan monastery. In spite of the trunk-loads of papers left behind after he choked to death over one too many a spicy morsel at his "last supper", the Master was adept at covering his traces: his ancestry and his provenance remained obscure; his arrivals and departures were always unannounced, and he kept his followers in a constant state of expectation.

Not for the first time, a shady eastern spiritual leader provides the vehicle for Ruth Prawer Jhabvala to illuminate aspects of the comedy of Western life. The destinies of four generations of a family are here intertwined around the enigmatic teachings of a doubtful mystic whose simple but eagerly digested message: "deny yourself, overcome yourself, transcend yourself", is lapped up by a society brought up to indulge, express and exalt itself.

Elsa Kopf and Hormusji Bilimeria (known as Kavi) - she from New York via 19th-century Germany, he a Byronic poet from Bombay - first meet at a reunion of the Master's early disciples in the Hampstead Heath home of Cynthia Howard ("about 35 at the time, with cropped hair and a monocle"). Elsa and Kavi marry and she gives birth to a daughter, but before long Elsa decides that she cannot bear to be apart from Cynthia and that their duty is to live together and work on the Master's behalf. Her daughter, Baby, is dispatched to New York with her discarded poet husband to live with Elsa's mother.

Kavi is just one of a cast of finely crafted and memorable eccentrics and innocents in this richly textured and witty novel. Another is his awkward, aloof, English son-in-law, Graeme, a Foreign Office philanderer who dislikes women even though he marries Kavi's daughter, rises to be deputy high commissioner in Calcutta, and retires to a sybaritic existence in London where he sits up in bed eating curry sent over from the Star of India and reading Annals of Rajasthan.

Jhabvala's characters are the most cosmopolitan in contemporary fiction. They hover between East and West, flitting from New York to London, linked by family blood-ties and shared memories which, in spite of failure, misfortune and infidelities, bind them together contra mundum. The world they inhabit and which initially seems so strange rapidly draws us in. Their creator is like some dazzling puppet master manipulating her characters in and out of time and space and through impossible situations we do not presume to question. Quite simply, this is how life is, she seems to say, and we must accept it or leave it. The different generations are effortlessly portrayed, whether in youth or old age. Her locations, too, are suffused in exotic atmosphere: a whiff of eau de cologne and cigars can evoke a Bombay club as intimately as do the Earl Grey tea and buttered crumpets that are used to convey Cynthia's Hampstead house.

It is left to Graeme's and Baby's grandson, poor, crippled Henry, who appears to have been personally chosen by the Master - indeed, he appears to have been mysteriously and immaculately conceived by him - to inherit both the burden of his mission and his trunk-loads of papers written in different languages at cafe tables all over Europe, as well as something of his aura. The movement lives on in the "Head and Heart House" he and his zealous family and followers found in a New York brownstone. They, and we, wait expectantly for some revelation, some tying up of fictional strands, but the Master's great message remains as obtuse as ever. We may feel momentarily perplexed but, as those who have seen the Merchant Ivory films she has scripted will know, in Jhabvala's novels there are never any easy answers. She remains, as VS Pritchett has said, "the detached observer of the comedy (in the sternest sense) which leaves us to make up our minds". There can be little doubt, however, that this is her best novel since Heat and Dust.