The book is 40% fascinating science and 60% bizarre, soapbox rambling across a range of the author's half-baked social, economic and political notions built blissful ignorance and relogious Americam exceptionalism.
The confidence with which the author ventures from areas of expertise into child-like simplistic commentary is astounding, and unfortunately makes much of the book insufferable.
First few chapters, and the one on terraforming are what you come for.