You can't beat The Second Law of Thermodynamics.

*******

Okay, it's really tempting to leave the above as the complete review but...
KSR has been something of a hit-or-miss author in my experience but this isn't so much hitting the nail on the head as firing a six inch nail from a nail gun through a tiny, flimsy piece of fibre board. Yep, KSR doesn't so much nail the target as destroy it. It's not subtle - KSR rarely is - he seems to have adopted Orwell's maxim about making one's meaning unmistakable in one's writing and made it his own to the extent that here it's literally made with a punch to the face. (That is if the word "literal" can be used to describe a fictional event.)

Anyway, KSR is yammering on about the same old same old environmental issues in typical strident fashion but using a story setting that is a significant departure from any of his previous efforts and taking a probably unique look at the old, old themes of the interstellar generation ship and AI, whilst working in a few philosophical questions about human nature, consciousness, decision making, language and metaphor and providing a fascinating, if occasionally repetitive narrative. It's a book whose assumptions and conclusions are going to piss off much of the typical SF fan-base, however.

Most of KSR's typical faults are dialled down here and this stands as one of his best works, though it lacks the sublime visionary heights sometimes attained in e.g. Galileo's Dream or the great adventure sequences of Antarctica.

Anyway, everybody should read this book and try not to shit in our nest, or at least use re-usable nappies, while we're doing it, because we've only got one...nest that is...and it needs to last us a long time.