This is a return to form for the author (after the very disappointing KRAKEN). It was a bit slow to start, as many of his books are, but once it got going, it was very thought-provoking. Conceptually and thematically very ambitious, he walks a tight-rope throughout and manages not to fall, to keep it all together, and to not lose me in the complexity of it all (much like the EXCELLENT The City & The City). Those expecting a space opera should be warned. THIS IS NOT SPACE OPERA.