The book only has 150 pages but there is a lot to learn here.
First, a few words about the author. Roy Spencer is one of the main people behind the technologies and algorithms to measure the global temperatures from the satellites - achievements that have been rewarded by various awards and that may be giving us the most accurate data about the global mean temperature that is available, even more accurate than James Hansen's GISS data, indeed. (But, despite some people's prejudices, Spencer has been funded from pretty much the same government sources as Hansen, except for those USD 250,000 from Heinz Kerry that Spencer sadly didn't receive.) He is also a very witty and comprehensible expositor who has been writing a website with cute parodies. Recently, he co-authored potentially important papers about the regulating role of clouds for the climate and about the uncertainty about the direction of the causal relationships between the clouds and the temperature.
In the book, he first introduces some basics of climate science and explains the nature of the scientific consensus. If the passionate reviewers below had seen the book, they would almost certainly appreciate it. Spencer reveals that the mankind almost certainly contributes something to the climate change and the greenhouse effect is nonzero, too. I know he has also patiently explained many of these well-known things to some of the less educated and more "radical" skeptics and his balanced treatment in the book wasn't a surprise for me. He is clearly no biased partisan.
However, he quickly turns his attention to a more important question, namely whether the human activity poses a danger for the climate. He explains that there exist no scientific papers that would offer reliable evidence of such a threat and he exposes various political, ideological, profit-driven, and other non-scientific factors that allow the irrational alarm about global warming to thrive and solid science about these questions to be suppressed and neglected. There is clearly no consensus about a dangerous global warming and after reading the book, you will see why.
If I were rating the author's opinions about the origin of the species, he would get less than 5 stars but I suppose this is not what readers should be rating here. This review should be about the book which is witty, technically solid - although avoiding equations -, and revealing the true major scientific and social aspects of the whole debate. Such a book from a qualified expert deserves at least 4.8 stars and I recommend it to you wholeheartedly.