David Mitchell is a tricksy novelist, but the tricks he plays tend to be structural rather than stylistic. He can do a number of different moods and genres, and often draws (with the self-consciousness of a good postmodernist) on the ideas of other authors. But it is the labyrinthine, almost Borgesian construction of his novels that makes them so appealing.
For several years, Mitchell lived in the Far East, and his first two novels, Ghostwritten and the Booker-shortlisted number9dream, are both set there. His new novel ranges more widely - across continents and time. Six narratives are grouped chronologically: the first is the diary of a 19th-century South Sea adventurer; the last a yarn spun round a campfire by a Pacific Islander. Between these two come a series of letters written by an English composer living in Belgium during the 1930s; the story of a hard-headed journalist's attempts to expose corporate greed and corruption in 1970s California; an account by an early 21st-century vanity publisher of his incarceration in an old people's home in Scotland; and the death-row testament of a genetically modified inhabitant of a futuristic, Orwellian dystopia.
Rather than allowing these narratives to proceed uninterrupted, however, Mitchell breaks off the first five in the middle, resuming them - in reverse order - after the Pacific Islander has completed his yarn. And in each case, the reason for the interruption becomes apparent only later on. All the narratives in Cloud Atlas (except the last) reappear in succeeding tales as physical documents, which the protagonists of those tales start to read, before being interrupted. So Cloud Atlas has an essentially dramatic structure: each narrative is "contained" within the next, making the novel as a whole resemble - as the author himself points out - a set of Russian dolls.
The effect is dizzying. The reader is flung forward in time and then propelled backwards to the point from which he departed. Yet Mitchell's aim is not principally to bamboozle. The six narratives of Cloud Atlas vary significantly in style and tone, but they are animated by a single theme - mankind's capacity for cruelty, rapaciousness and violence. In each narrative, Mitchell describes a different form of subjugation, ranging from the petty tyrannies inflicted on the occupants of the old people's home to the terrifying scenario of genetically modified "fabricants" being bred to cater to the needs of an ascendant "pureblood" population. It is only in the final story, however, that the devastating consequences of such behaviour are revealed.
Mitchell's structure has one significant drawback - it disappoints our wish to know what happens. It is hard to rekindle our interest each time he resumes one of his tales, especially as we know how things end up. But this is where the trick of time-reversal proves invaluable. During the first half of the novel, mankind appears to be shackled to its destiny. The momentum of time seems impossible to resist. But in each of the resumed narratives, Mitchell offers a different perspective: people, it transpires, are free to make moral choices; if only humanity can harness its capacity for selflessness, it is not too late to alter the course of history.
This, it hardly needs saying, is not an original idea. But, as one character points out, "as if there could be anything not done a hundred thousand times between Aristophanes and Void-Webber! As if Art is the What, not the How!" In Cloud Atlas, it is certainly the how, and not the what, that is enthralling.