An excellent plot-driven, action-packed story. He creates a wonderful world where nanotech has all but destroyed the value of 'things' and increased the value of high-quality knowledge and split the world into a utopia-dystopia. All good SF stuff and references aplenty for those who like to play those games. One of the nice things is that he doesn't bother to over-explain or moralise or erect a big sign saying "dangers of nanotechnology". What it isn't is a hard-sf book on nanotechnology nor is it a book with a point; if you want the characters problems to be resolved and everything to be tied up neatly at the end then brace yourself, this book sets up more questions than it answers and rather abandons the reader before things have reached a truly satisfying conclusion. Only a writer with the creative depth of Neal Stephenson could afford to throw ideas of this quality away. Excellent, but falls a little short of genuine read-it-fifty-times perfection.