Natural History begins with the cover: a very nice design by Steve Stone, depicting the novel's opening moment, which almost acts as part of the narrative. What follows is a strong piece of writing that I (and others) was surprised didn't make the 2004 Arthur C. Clarke Award shortlist (although it was nominated for that year's BSFA Award). The nomination of the book for this year's Philip K. Dick award, therefore, is welcome.

Natural History is a novel of a future somewhere in the middle of the third millennium. Humanity has expanded through much of the solar system, but that expansion has been in a non-traditional fashion. This is a society that is heading towards one version of the technological singularity, that based upon the redevelopment of the human form and human mind—the sort of posthumans depicted in the Shaper/Mechanist stories of Bruce Sterling. Ordinary humans still exist; they are the Unevolved, or more contemptuously, "monkeys," and they are keen to maintain their position at the top of the social hierarchy. For the most part, they remain on Earth.

Space is mainly the province of the Forged, humans grown into new forms suitable for travel between the planets, though Forged are also found throughout human society. Forged are created for a wide range of purposes; as well as transport between planets, there are Forged to work heavy lifting jobs, to deliver messages, to act as space combat vehicles, and to perform all tasks up to and including terraforming. There are Forged in the shapes of beasts, Orniths and Arachnos.

But many of these new humans feel frustrated by their lot, trapped within the functions they have been designed for. Then there are the Degraded, Forged for whom something went wrong in the growth process. They feel resentment towards a society that has little or no use for what it did not intend to create. Out of all these tensions, an Independence movement is growing, of Forged who want to make their own destiny, who resent the claims to superiority and right to govern taken by the Unevolved, and who reject such a hierarchy as false. (Others reject the Independence movement's pretensions.)

The novel begins with that cover: with Voyager Lonestar Isol, a deep space probe and leading light of the Independence movement. On her way to Barnard's Star, she encounters what comes to be known as "Stuff," a wondrous material that allows Isol to grow an engine that enables her to cross the Galaxy in an instant. No one is quite certain of the nature and purpose of Stuff, and many, particularly the Unevolved, are deeply suspicious of it. The exploration of Stuff will involve not just Isol, but also: Corvax, a Forged Roc (Handslicer Class) conducting illegal operations with the Uluru, the virtual "dreamtime" in which the Forged's consciousnesses are raised; Zephyr Duquesne, an Unevolved historian; Tatresi, a great Forged transport; the Degraded eagle Gritter; Trini, a member of a hive-mind Ticktock; and General Machen, an Unevolved general of Gaiasol, the solar system's governing agency. At the end of the novel the human race's relationship to Stuff remains highly ambiguous.

I have now read this book twice. The first time, I found it interesting, but hard going in places. I think this is because I often found it hard to visualize the Forged, and sometimes imagined them as looking like normal humans. Pete Young, editor of the Nova-winning fanzine Zoo Nation, has said to me that it was very hard to get any sense of scale. It is worth noting that when talking at a meeting of the British Science Fiction Association, Robson herself said that she didn't really describe what the Forged looked like, because she couldn't really see the point. I wonder whether this is because the Forged, conceived and raised in virtual reality, don't have a self-image that correlates with their actual physical form, but this doesn't seem to be a conscious decision on Robson's part.

The Forged remind me in a number of ways of the great sentient ships of Iain M. Banks' Culture novels. The difference is that while the Forged are human, the Culture vessels are controlled by AI Minds. Now, one might think there's actually not much of a difference there, but in Natural History the distinction between being human and being AI is crucial. The Forged are alive, whilst AIs are merely very, very good simulations of sentience. This is quite categorically stated by Zephyr's Abacand, the most prominent AI in the novel.

"It is the arising of sentience from insentience that is the heart of the mystery, I think," the Abacand hazarded. "That and the assignment of meaningful importance to random matter. I do not do this last thing. I do not need a meaning to my existence, nor do I impose one on the universe. In that sense I have no creativity, and nothing to contribute to this collective consciousness [the consciousness behind Stuff]. So, I am uninteresting to them and incapable of communicating with them." (p. 312)

But this raises a question Robson doesn't really address. The Abacand is as fully-formed a personality as any of the humans in the novel. There is no verifiable difference to an outside observer in the signs of sentience. Yes, the Abacand has been designed and programmed to behave in a certain way. But Voyager Isol herself has been nurtured and conditioned for a particular role, and her personality moulded to fit. Is there a difference?

The other aspect of the novel which I found problematic on first reading was the proliferation of ideas. I couldn't help feeling that Robson might have been better off concentrating on one or other of the main themes. It's never quite clear, for example, whether the alien Stuff is a McGuffin to allow Robson to explore the post-human universe of the Forged, or whether the Forged are a McGuffin to allow examination of the extra-dimensional communal mentality that is behind Stuff. In the end, I think Robson tries to do both. As a result, we end up not learning as much about either as we'd like. (Although the nature of Stuff is explored further in the sequel, Living Next-Door to the God of Love.)

During my second reading, however, these issues seemed less important. Certainly, it became significantly easier to visualize the Forged as the non-human entities that, in appearance at least, they are. And the novel became more coherent. The connections between the disparate elements seemed clearer. The nature of Stuff, which is bound up in notions of eleven-dimensional existence, seemed less beyond the comprehension of everyday readers. Or perhaps I've got more used to reading about post-humans in the intervening two years.

Despite my comments above, Natural History is an excellent example of twenty-first century British SF. Oddly though, I find it quite hard to put my finger on why this is the case. I've found this when I've written or spoken about this novel in the past—I can see and describe the work's flaws quite well, but when it comes to the strengths, whilst I'm aware that I enjoyed the book, I can't always say why. However, part of the answer, I think, is Robson's ability to do rounded characterisation. She produces a series of portraits of individuals about whom the reader cares, and whose point of view can be understood, if not necessarily agreed with (there are no real villains in Natural History). And there is a clever imagination at work here. The novel certainly does not suffer from a shortage of ideas—as I said earlier, if anything, there is a surfeit. As a result, Robson's work can comfortably claim a place alongside the likes of Ken Macleod's explorations of machine intelligence and posthumanity.

Niall Harrison, in a review of Living Next-Door to the God of Love in Foundation 96, remarks: "[a]t the end of Natural History, humanity grasped the possibilities offered by Stuff ... with both hands." This does not seem to me to be an accurate reading of Natural History's conclusion. Some characters do grasp the opportunities—Corvax, Zephyr, Trini, Isol. But many more humans and Forged remain deeply suspicious and afraid of being transferred into Stuff, not least because Stuff tends to assume a consensual response before the responder has fully understood the question, and no chance is given to change one's mind. Isol only gives in to Stuff because she realizes that there is no escape, and Trini's Hive Queen kills herself and all Trini's sisters out of fear of contact with Stuff.

Nevertheless, I'm grateful to Harrison for this misreading, as it has allowed me to unlock what I believe the novel is about. On one level, Robson is playing with notions of the Singularity, by having a society transformed by one sort of post-humans, the Forged, encounter another type of Singularity, a universal consciousness. But on another level, I think that Stuff may be a metaphor for death. Death takes our individuality, just as Stuff does, and most of us fear it, and the loss of that individuality, just as many of the humans in Natural History fear Stuff. Even where one does not believe that death is the end of existence, some belief systems see it as some sort of transition, "becoming one with the universe," which can be a frightening prospect (and is exactly what Stuff causes). On this reading, it is a deliberate part of Robson's design that Isol's first encounter with Stuff comes at a moment that she believes to be (and would be without the intervention of Stuff) her own death.

And, having done Death, it's not surprising that Robson moves in her next novel to Love.

Tony Keen moonlights as an academic and critic, when not earning a crust. His chapter on Jeff Noon's Vurt is forthcoming in Paul Kincaid, Maureen Kincaid Speller and Andrew M. Butler (eds.), The Arthur C. Clarke Award: A Critical Collection.