There is no simple way to approach Cloud Atlas, the new novel by British author David Mitchell. Begin with the story or, rather, the stories. There are six of them and they range from the historical to the speculative, the thriller to the burlesque. The book is constructed like a Russian nesting doll: one tale buried inside the other, with a core narrative at the centre. Plots are interrupted for hundreds of pages, often in mid-thought. Connections are subtle and, amid the razzle-dazzle, easily missed.

Summaries of these stories may or may not help the cause. To say that the novel opens and closes with the journals of Adam Ewing, a 19th-century American lawyer travelling the South Pacific during an era of brutal colonization, is to say very little. Ewing's tale, for instance, soon gives way to the epistolary musings of Robert Frobisher, an amoral young composer in 1920s Europe. Frobisher writes the Cloud Atlas Sextet while scheming to advance his career through his association with a musical recluse, a figure modelled, possibly, on Frederick Delius. He also discovers a partial volume by a man named Ewing, who "never saw the unspeakable forms waiting around history's corner." Letters from Zedelghem is story number two.

A 50-year leap brings us to 1970s California and Half-Lives: The First Luisa Rey Mystery. The genre now is pulp fiction, and Luisa is a reporter investigating an American-sized paranoid conspiracy at a nuclear plant. She gets her break from the friend Robert Frobisher was writing to, a veteran scientist with an upcoming date with a bullet.

Abandoning her in mid-peril, Cloud Atlas presses on to the misadventures of one Timothy Cavendish, a London vanity publisher who winds up incarcerated in a prison for the aged. He, by the way, is considering a manuscript about a California journalist mixing it up with corporate baddies. It's a thriller (number three) and The Ghastly Ordeal of Timothy Cavendish (number four) is pure burlesque.

Next, there are science fictions, both of the near and distant schools. An Orison of Sonmi-451 offers a clone, genomed to work 19-hour days in an underground fast-food restaurant, being interrogated in the wake of her arrest. She has dared challenge her fate and live as a human. The story occurs in a still-recognizable Korea, where the replicant, named Sonmi, offers comments such as the following explanation of her travel itinerary as a fugitive: "An abbey stood there for 15 centuries, until corpocracy dissolved the pre-consumer religions after the Skirmishes." She, it seems, watches an old film starring a character named Timothy Cavendish – a tenuous link, at best.

Finally, at the pulsating heart of the book is an 80-page novella written in the pidgin English of a post-Armageddon future. In Sloosha's Crossin' an' Ev'rythin' After, the narrator Zachry, member of a Valleysmen tribe who worship the god Sonmi, begins his tale of hunter-hunted with a line that demands a good deal from the already bug-eyed reader: "Old Georgie's path an' mine crossed more times'n I'm comfy mem'ryin', an' after I'm died, no sayin' what that fangy devil won't try an' do to me..." Zachry, it is perhaps – or perhaps not – helpful to mention, lives in an environmental disaster that was once Hawaii.

But such frantic, and unavoidably glib, synopses don't quite explain the core challenge in discussing Cloud Atlas. The issue is more one of credulity. How could the novel just described ever succeed on the page? How could any reader be expected to follow such a scheme?

True, David Mitchell, though only in his mid-thirties, has already published two astonishing novels: 1999's Ghostwritten, and number9dream, short-listed for the 2001 Booker Prize. He has established a capacity for multiple cross-plottings and the effortless occupation of wildly disparate characters and voices. Couple these gifts with a fierce attachment to language, and to the structural rigours of the literary novel, and you have a rare, and somewhat reckless, talent. No question, Mitchell is both the real deal, and a real believer in the form he seems determined to advance.

Still: six plots spaced over vast expanses of time and history? Incredible as it may sound, Cloud Atlas works in nearly every regard. The innermost Russian doll, Zachry's grammar-challenged tale, can be tough going in spots, and the plunge into the SF vocabulary of An Orison of Sonmi-451 is jarring, like a winter dip in an icy lake without benefit of a preceding sauna. Some may grow impatient with how openly Mitchell wears his influences – Martin Amis and Don DeLillo, J. G. Ballard and the Russell Hoban of Riddley Walker, to name just a few – although their shadows are, I suspect, intentionally left large, part of the novel's implicit argument about fiction and forgetting.

These, however, are quibbles, set against the achievement of these audacious narratives. An equal feat, and a reason why the book is, in the end, accessible, lies in the clarity and propulsion of its core theme. In every story, Mitchell charts some act of predation, of humans preying upon one another, either as individuals or societies. According to Cloud Atlas, while this species characteristic is as eternal as the Garden of Eden, we tolerate it at ever-greater risk of self-annihilation.

Sloosha's Crossin' an' Ev-rythin' After may be set in America's private Eden to reinforce the point. We are now capable of falling so far we could end up back in that proverbial garden, illiterate and vulnerable. Ronald Wright's novel A Scientific Romance made a similar point, with similar ardour, a few years ago.

Cloud Atlas is, obviously, a formidable creation. Graham Greene once praised a daunting Henry James novel by comparing it to a cathedral. Greene was referring to the book's architectonics, and was speaking as someone humbled by the artistry of a colleague. Fellow novelists will find it hard not to heap similar praise on David Mitchell, whose brilliance takes one's breath away in a manner not unlike a first experience of Chartres or the Duomo.

What, though, of the reader, who is rightly interested less in the details than the final effect? Maybe the cathedral simile can still apply. Here is a dome so grand, and so ornately decorated, that one has trouble appreciating its entirety without causing neck damage. Still, it is a pleasure to sit inside such an edifice, and to marvel. Repeat visits are in order. Each time, a little more structure is revealed. Each time, the space grow less intimidating. Until, finally, it is just a book, one that you are reading with amazement and delight.

Luisa Rey's Hitchcock

"Hitchcock loves the limelight," says Luisa, her bladder now growing uncomfortable, "but hates interviews. He didn't answer my questions because he didn't really hear them. His best works, he said, are roller coasters that scare the riders out of their wits but let them off at the end giggling and eager for another ride. I put it to the great man, the key to fictitious terror is partition or containment: so long as the Bates Motel is sealed off from our world, we want to peer in, like at a scorpion enclosure. But a film that shows the world is a Bates Motel, well, that's ... the stuff of Buchenwald, dystopia, depression. We'll dip our toes in a predatory, amoral, godless universe – but only our toes. Hitchcock's response was" – Luisa does an above-average impersonation – " 'I'm a director in Hollywood, young lady, not an Oracle at Delphi.' I asked why Buenas Yerbas had never featured in his films. Hitchcock answered, 'This town marries the worst of San Francisco with the worst of Los Angeles. Buenas Yerbas is a city of nowhere.' He spoke in bons mots like that, not to you, but into the ear of posterity, for dinner-party guests of the future to say, 'That's one of Hitchcock's, you know.' "

– from Cloud Atlas