It's good to see nanotech books finally beginning to proliferate on the sf shelves. As someone who read K. Eric Drexler's Engines of Creation with unadulterated awe a few years back I've long been waiting for them to appear. There was something of a false start with Greg Bear's Blood Music back in, ooh, donkeys years ago; Neal Stephenson's The Diamond Age failed to quite ignite the zeitgeist, and Kathleen Ann Goonan's Queen City Jazz was just too… convoluted (and had too much jazz in it for my liking). This new genre still needs a handy name to pigeonhole it though - "nanopunk" or something.

Bloom sounds as though it might be the wide-screen novel nanotech sf needs to kick-start itself. The entire inner solar system has been taken over by a self-replicating nanotech (here referred to as "mycora") bloom that has converted every piece of solid matter - 99% of the human race included - into more nanotech.

The remaining 1% of humanity has escaped to the moons of Jupiter and the more reckless ones the asteroid belt. They've managed to survive there for almost 30 years because the bloom cannot replicate nearly as efficiently in these cold outer wastes. Now, however, things are beginning to change and the first mission is being sent sunwards in a specially prepared ship.

As soon as I read the cover blurb I couldn't wait to start reading Bloom, and then once I'd started reading Bloom I couldn't stop, being a sucker for "end of the world" novels - and this is an end of the world novel big style, it's the end of most of the solar system and possibly the galaxy, because of the relentless propensity for growth of the mycora. With the fear of the bloom menace has come a rejection of many new technologies; our narrator, John Strasheim, is a sort of two-a-penny internet writer by night, but a fearless cobbler by day. The impression given of the colony he lives in on Ganymede is a confusing mix of steampunk and the internet.

Anyway, Bloom is a lot like Michael Swanwick's Vacuum Flowers in its tour of the outer colonies revolving around a lost Earth, but not quite as exotic. The visit to the "Gladsider" asteroid colonies is interesting but the flight into the inner system that follows suffers a little from spaceflight's biggest narrative hurdle: the essential tedium of flying through an enormous amount of empty space in a very small box.

McCarthy actually does a respectable job of keeping the narrative flowing: the mechanics of the ship (the Louis Pasteur) are interesting to get to grips with and, certainly earlier on, the bloom is a very very potent threat. There are some excellent "extracts" from Strasheim's earlier writings that function both as an excellent device for infodumping and to give the reader a healthy respect for the mycora outbreaks that the Ganymedeans and all the remnants of humanity live in fear of.

However there's an annoyingly wilful blindness on the part of all the main characters throughout with regard to the bloom. Despite distinct and regular references to the bloom's incredible size, complexity and speed of development not one of the characters entertains the idea (not in front of our narrator, anyway) that the bloom might be anything other than a mindless, exponential, world-eating plague.

Despite everything I've just said I enjoyed Bloom a lot. It's hard to write nanotech sf precisely because the implications of a working nanotechnology just about take us out of sf and into fantasy. Any society that has nanotech is not going to be much like ours and it's hard for sf to reflect anything that we might know or recognise within that.

Wil McCarthy's take on nanotech sf may just be about as far as we can go with the idea in fiction; standing on the very fringe of this incredible thing, scared to dip our toe in because everything will be different afterwards. It's not a very satisfying conclusion but nonetheless it's worth being along for the ride.

Just as a postscript, John Strasheim refers throughout to "Conway's Game of Life", which for those who haven't seen or heard of it before is absolutely fascinating and available to download for Windows from http://psoup.math.wisc.edu/Life32.html