Not sure how this got 4 stars..... it reminds me a lot of Asimov's Foundation books that I enjoyed so many years ago - the characters are all pretty wooden, the plot thin and there are an awful lot of descriptive passages describing Mars that it is a temptation to skip over. However the real characters are the place and the social and cultural structures being changed and built and destroyed. The problems being addressed are all very real in the world right now. And that is the strength and triumph of science fiction. Here it is done very well and while you may not care very much what happens to any of the individuals, you are led to care intensely about the society. He has also obviously paid a great deal of attention to what is known about Mars and to the physics involved which gives it a great up to date feel - although in the long run may get out of date so perhaps best read this decade! I shall not wait too long before tackling 'Green Mars'.