The Hot Topic is an exemplary piece of science writing. It spells out the issues clearly and rationally, and presents evidence and analysis of supporting research.
I hope this book will reach a wide audience, because it educates the reader by informing but not by invoking mass hysteria (as, unfortunately, some mainstream media seems to view as essential when discussing this topic).
My only criticism would be that the subject is obviously very complex, with a number of interdependencies between climatic effects (e.g. positive feedback loops). More graphical representation of all this would be helpful for the layman. I found myself needing to go back and re-read some sections to keep all the concepts in my mind, and a few more diagrams would probably make for a useful, and more rapid, reference. However, the format of the book would probably need to be larger, and glossier, to do that successfully, and I suspect the cost would go up accordingly. This book is something that needs to be read by as many as possible, so producing it cheaply is probably wise. It would be great to see it on the national curriculum as a science text book in future.
Let's hope that Gabrielle Walker and Sir David King write a follow up handbook, for those that wish to pursue the topics further. They've certainly done a great job with this book.