The Slumdog Kill-ionaire is back, reminding us how exhilarating fiction can be when novelists finally leave their seminar rooms and dive into the real world. The Indian writer Aravind Adiga won the Mann Booker Prize last year for The White Tiger, a story of an Indian slum kid who rises to riches by killing his boss. Now he has followed it with Between The Assassinations, an armoury of short stories about a typical Indian city as it rises with a great heave from poverty to power (for a few).
Adiga has become great by ignoring the cliched advice given to all young writers, which has long since hardened into a dogma: write about what you know. He is from a typical rich Indian family insulated by servants who are treated as invisible.
He is so talented he could have made that world interesting, for a while, in its small way. He could have done what too many British and American novelists are doing, and ever more exquisitely described his own navel.
But he chose instead to write about what he didn't know - by going out and discovering it, like a journalist. Between The Assassinations enters into the heads of a panorama of 21st-century Indians, from rich kids tossing bombs at the caste system, to women steadily going blind in sweatshops, to rickshaw drivers slowly pedalling their bodies into broken sinew.
He learned about their lives by going out into the streets and writing about what he found. It is a return to the great realist novels of the 19th century, when fiction captured the tectonic shifts altering our world by showing how they changed the characters of individual men and women, one by one. It's Charles Dickens in a call centre; it's George Eliot adding credit to her mobile phone.
Through his perfectly observed characters, some of the transformations of our time become clear. To name just one, the great shift in power from the West to the East takes on human form, where we can understand it best. The narrator of The White Tiger writes to the Chinese Premier, Wen Jiabao: "Don't waste your money on those American books. They're so yesterday. I am tomorrow. This is the century of the yellow and the brown man. You and me."
Yet as they wait for this new world, Adiga shows how most Indians have to sweat along, one screw-up away from destitution. As another of his characters says: "The rich can make mistakes again and again. We make only one mistake, and that's it for us."
There was a time when it seemed natural - obvious, even - for novelists to go out into their societies and describe them like this. As the mega-selling author Tom Wolfe says: "Dickens, Dostoevsky, Balzac, Zola, and Sinclair Lewis assumed that the novelist had to go beyond his personal experience and head out into society as a reporter."
Dickens was constantly charging out into the "Great Oven" of the London night to witness its endless churn. Emile Zola went down the coalmines at Anzin so he could capture their dark dust-filled world in Germinal. John Steinbeck bought an old pie truck and drove down to live in the squatters' camps filled with people fleeing the dustbowl, and it gave birth to The Grapes Of Wrath. Graham Greene trawled across the dictatorships of the Caribbean and Latin America before writing his novels about them. George Orwell and Ernest Hemingway went to the Spanish Civil War before they smelted their masterpieces about it. Reporting didn't smother their imaginations, it fertilised them.
Yet there are so many talented young novelists I have read who seem to think the real, heaving world outside their study is a vulgar concern to be left to journalists and TV series like The Wire. They prefer to write books that ruminate on how epistemologically hard it is for "The Novel" to describe the real world, or to retreat into the stories of the distant past, or to concentrate on endless tales of middle-class adultery.
In the 1950s it became popular to say the realist novel was a dead form, belonging to the dull brickwork of the 19th century. The world now is too fast, too chaotic to be captured that way. But what could be more fast and chaotic than an Indian city at the birth of the age of the East, where a rickshaw-driving skeleton is pedalling a fat man who is merrily texting New York? Adiga makes it seem like the realist novel was designed to describe just this juxtaposition, on just this day.
When it is written with skill, the realist novel is always - yes - real. Wolfe, one of the great champions of the journalistic novel, warned a decade ago: "The American novel is dying not of obsolescence, but of anorexia. It needs food. It needs novelists with huge appetites and mighty unslaked thirsts for America, as she is right now." He says it would be "a revolution not in content, but in form".
The same goes for the fiction of the wider world. It's not that there aren't other great types of fiction - I love Jorge Luis Borges and Philip K Dick, and it's impossible to imagine either of them going down a mineshaft with a notebook.
But Adiga has reminded us that the big realistic novel has enough adrenaline to draw in millions of readers. His was the best-selling Booker in years, because it wasn't some abstruse literary experiment, it was alive.
There are many bold writers in the West who are still acting on these reportorial impulses, from Dave Eggers to Monica Ali to Irvine Welsh - but there are not enough. I ran into John le Carre in the war zones in Congo, researching his novel The Mission Song, and I thought, "Where are the others?" Wouldn't Greene have decamped to the Green Zone in Baghdad? Wouldn't Hemingway be in Helmand and Orwell in Burma - or at least in the abandoned mill towns of the North of England? How many great novels are going unwritten today, because novelists are not being urged to make these journeys into reality?