ARCADIA
By Iain Pears
Faber and Faber, $29.99.

Reading this novel I found myself thinking longingly of the three volume novel of the 19th century. Arcadia is very big and heavy. And that's the proof copy; the hardback must be worse.

And then I discovered that it was spec fic – speculative fiction. Not my favourite genre. But I should say that quite shortly neither of these drawbacks worried me at all. I was entirely captured by its narratives. There are three of these. To begin with there is a pastoral idyll, possibly, which turns out to be written by a fellow at Oxford in the middle of last century; this is the second strand. He is conscious of Tolkien and C.S.Lewis in this mode, and speaks dismissively of Lewis, so suburban, with "that bloody bore of a lion of his". Lytten's particular interest is Arcadia, Philip Sidney's epic poem, lacking "plot, action, events, morality, structure, or pace", none of which is a problem here: plenty of plot, action, strange characters, and much of a moral nature to think about. What Arcadia does have is a landscape that is a dream of perfection. And beautiful language.

The idea of Arcadia does necessarily have its ironic elements. Oxford in the 50s is not an ideal place, and when we get to the third strand, some several hundred years in the future, we are in a narrative very like Huxley's Brave New World, with no plants or animals, a ruthless elite, a tyrannical hierarchy of power, and a slave population kept acquiescent with drugs.

What links these three different worlds is time travel. Angela Meersom, in that dystopian future, has developed a machine that is supposed to move between parallel universes, but doesn't, it goes backwards or forwards in time. Iain Pears doesn't bother us much with the physics of this, since they don't exist – though he does say it is a bit like cutting and pasting on a computer – but he does nod in the direction of the conundrum, if you travel back in time and kill your grandmother before she has any children, then you won't exist, though he does not subscribe to the Doctor Who adage that the time traveller must change nothing – so you can't go back and get rid of Hitler, for instance. Maybe if you do you get the parallel universes that the machine was designed to tap into.

Pears' prose is a pleasure to read. It's not present tense, it does not strive after metaphor, though there are some nice ones, it captures its diverse settings and characters. It's often funny, as in the descriptions of the machine that Angela builds in mid-20th century Oxford (she travelled back to the 30s, had a good war in British intelligence and the French Resistance and became a good friend and colleague of Lytten) fashioned out of a Victorian garden arch controlled by a kettle and saucepans, which she keeps hidden under a bit of cloth in his cellar.

Lytten's fantasy world is called Anterwold, a simple society of farmers and peasants with no technology beyond the wheel. Its centre is the town of Ossenfud, inhabited by scholars whose role is to keep alive, to protect and elucidate the story which is the raison d'etre of the society's existence.  The storytellers know everything. "How the world was, how it operated, the laws of men and nature and of God." They not only possess this knowledge, they keep it safe. This is a completely static society, until Rosie, a schoolgirl who sometimes feeds Lytten's dreadful cat, accidentally enters it through the arch in the cellar and sets it going in time. She makes things happen.

It's been a very formal society, governed by strict protocols of behaviour and of words; you must say the right thing in the right place. Life is hard, but at the same time it can be benign. There are good rulers who look after their people. But Rosie sets in train movements which drive the whole thing to become more fluid, to become a place that exists as something more than a story.

It might seem that I am giving away a lot of the plot, but in nearly 600 pages a great deal more than this occurs. Curiously, when I was about 10 pages before the end I thought Pears was going to have to sort all this out in a great hurry, but he makes no attempt to do so, he sets everything up and leaves us to decide what is going to happen. What will become of Rosie? Of the earth? With a bit of careful thinking we can work it out, but will we be right? It doesn't matter, the story whatever it is has its own validity. And anyway Lytten is not sure what the ending should be.

I only found one slip on the writer's part. Angela thinks at one point that everything will depend on who is American president at the time of the Cuban missile crisis, still some years off.  She knows about the crisis because she comes from the future, but in that case she must know that it's JFK – he is inseparable from that event.

The cross-referencing of the three stories makes for a compelling narrative; switching from one to another means we are constantly in a state of suspense. It would have been easier to read in three volumes, but quite quickly it didn't matter, the book is so captivating.

Marion Halligan's latest novel Goodbye Sweetheart is published by Allen & Unwin.

* Pears says Arcadia is a novel conceived and written for an app. Download free from iTunes: http://apple.co/1NyEGLw and visit arcadiatheapp.com to unravel the story of your own making.