What can I say that has not already been said about David MacKay’ outstanding book on Sustainable Energy? It won plaudits from a wide range of reviewers (from the right and the left, from greens and cynics) and became one of the hottest selling non-fiction titles ever on Amazon.

So why all the hype about a book which essentially takes all the major sources of energy and piece-by-piece examines their current impact and potential future contribution to a low carbon world?