Imagine a world. It might be this one.

Imagine a world in which you’re taking part in a war: a war against an enemy you can’t quite define and don’t wholly understand and who may not exactly be the enemy anyway.

Imagine a world in which you’re just a passive observer of all the action undertaken by other people, able to move about and observe but prevented from fully interacting with those you spend the most time with.

Imagine a world in which your value to other people depends on you not knowing exactly what it is you’re doing. In which no one understands you, although they think they do. In which the levels of your mind that you thought were hidden seem to be getting out.

Imagine a world in which your life is screwed, although you don’t yet know quite how badly.

Imagine that there are several different worlds, with some connections you haven’t quite been able to puzzle out yet, and that you can move between them although you don’t have much control over when, or indeed over anything much else in your life.

Then tell me where the real world is, and how you can get there.

Now you know what it’s like to be a character in this novel, or at least the character whose viewpoint we share. And now you know what it’s like to read the novel as well.

Double Vision is Tricia Sullivan’s fifth novel, and in it she has created a tantalising network of experience. That’s not just a description of how the narrative works; it’s a major part of the landscape. In the world there is the Grid, and in the Grid there is a war, and in the war there are many soldiers. One small team of soldiers are being watched through the eyes of their own surveillance equipment, a native lifeform who has been slaved to their system, and who has an unexpected observer riding pillion in her mind.

Karen ‘Cookie’ Orbach is an unreliable narrator in an unreliable world. She reads science fiction and fantasy, but she can’t watch it on tv because when she watches tv she tunes into something else entirely: the world in the Grid or, perhaps, the Grid in the world. And that’s what she does for a living: she is the observer. She’s been doing it for long enough that she can begin to put some sense on what she’s seeing, although maybe it’s really because she’s psychic. What she can’t work out is all the questions her boss wants to ask her when she’s finished, or why he doesn’t seem so interested in the bigger picture of what’s actually going on in the war. But she keeps doing it, because what else can she do? And because she thinks she’s able to do at least some good. And because in the Grid, at least, she can fly.

In any case, Cookie has problems of her own. She’s overweight. Her mother won’t stop nagging her about getting a boyfriend. Her colleague keeps making her go to karate, where the gender politics help to remind her why she hasn’t got a boyfriend. And that’s before everything gets difficult.

This novel goes beyond the usual SFnal technique of making the reader question observed reality. It makes you think about how much reality can be real at once. It makes it impossible to write about ‘the main narrative strand’ and be confident that another reader would agree about which one that is. You can at least tell which narrative you’re in by following the typography—probably.

Each narrative deals with perceived reality; and with violence and death; and with sustenance and life; and with the relationships women have with one another, and with men, but most of all with different kinds of control. Each narrative is bound to the other, but—as with Sullivan’s previous novel, Maul—it’s not immediately apparent whether one is driving the other. And it leaves a number of other questions unanswered, at least on a first reading, about how many connections there are, and what they mean, and what, therefore, the novel is really about.

There are some flaws, or at least points where the blurring of reality sends a mixed message instead of presenting a thought-provoking dilemma. For a novel that otherwise scores as feminist science fiction for the new millennium, it seems rather too edgy to have Cookie embarking on an extreme crash diet that mirrors an eating disorder; yet in this, too, the narrative bends but does not break, since it enables a different perspective on control as Cookie experiences violent impulses she now, like the soldiers she has observed, has the strength and skill to follow through.

Alongside the feminist reading, there’s also a post-colonial subtext to be extracted from this novel—although maybe that’s currently true of most novels, depending once again on the observer more than on what is observed. Nalo Hopkinson, launching the post-colonial anthology she co-edited with Uppinder Mehan (So Long Been Dreaming) at the SF Foundation’s 2004 conference in Liverpool, commented that SF authors writing black characters usually have to find a quick way to tell a predominantly white readership about their ethnicity, so that they read true. Sullivan waits at least a couple of dozen pages before she gives anything away explicitly, and in doing so plants the seed of a question about many other characters. The names of the soldiers, at least, suggest a multicultural society, and this background adds yet another dimension to an attack on the Grid that uses women as the instruments of colonisation because direct male approaches have failed. But nothing is simple. Nothing can be taken for granted. Little is as it first appears.

So read Double Vision. And then read it again. And then tell me where the real world is.

Claire Brialey is the awards administrator for the British Science Fiction Association; she also reviews for Vector and Foundation, was a contributer to Damien Broderick’s Earth is But a Star, and co-edits the SF fanzine Banana Wings. She works as a civil servant for the UK Government.