Much has changed in the 3 years since the first edition of this book. The physics of heat, light, sound and energy is still the same, so there is little change in the first three parts. Apart from the correction of a few errors, a few new developments are mentioned, some new methods are included and statistics updated. Part 4 has many new elements that reflect societal changes, especially changes in public attitudes. Three years ago there were many who denied global warming or who regarded renewable energy technologies as ‘ kids ’ stuff ’. Today only a few of these survive. Global warming is recognized as a fact.
