I read this recently, but haven't written one of my longer posts that usually go up at Suite101.
At first I was unsure whether I would get through the book, as there is a lot of science in it. But Hansen's gentle demeanour and avuncular manner kept me reading.
This book is well worth looking into, as it goes into how science in general works,. ie. there is a lot of scepticism built into it.
A lot of the conclusions of the book are extrememly alarming. Hansen is mild-mannered, but the overwhelming evidence of the science has pushed him into activism and book writing to get the climate change science to the public.
If you want to get a close insight into how the front line science on this issue works, written in a friendly and engaging manner, then get this book.