This book is very much to do with the theme of the 'gods', which Macleod introduces in Cosmonaut Keep, as well as the story of the Second Sphere.

Character Development - 10/10
What is there to say? Macleod's development continues to be imaculate and does so through-out the trilogy, not to mention his other work.
(See my review of Cosmonaut Keep for more detail)

Story - 08/10
The planet, Croaton, that Matt and others arrive on is seperated between two peoples. First of all, the 'Sky People', who are almost like American Indians - extremely low-tech and almost tribe-like. On the other side of the scale, however, is the peoples of 'Rawlistone', who are very high-tech, with things such as 'Garvity Skiffs' (flying saucers) and Trade Ships. Now, the two races don't get on and from the beginning it's obvious what's going to happen.
Some aspects of this book can be somewhat slow, in the sense that it's much to do with the two races, who you don't find yourself overly-interested with. It does show, however, human nature, and how the strong kill-off the weak, which isn't necessarily nice but nevertheless true. By Macleod creating a kind of 'American Indian' vrs. 'White Man' scenario it helps us see human ignorance. If it weren't for the 'Sky People' then Matt and others wouldn't have been able to contact the Gods and learn key information that allows their story to go on. This brings me to the over-lying theme - the consequemces of actions, right down to an individual level - which is especially brought through in the Final Volume (Engines of Light).
The last third of the book is a complete turn-around, and extremely quick paced that keeps you turning pages for hours. It makes-up for any boredom that may have been present during the fist part and then gives something extra. Don't give up on this book.

The ending is pretty much perfect. It leaves you breathless for a few seconds whilst you come to terms with everything that's happened. It also gets you hyped for the remaining volume, which is my personal favourite.