In preparing this second edition I have increased the number of engineering examples, both in the body of the book and in an additional chapter based on my own experiences. I have also seized the opportunity to introduce more up-to-date material, to improve the clarity in some sections and to introduce some more interesting illustrations of principles. I hope and believe the result is a better book, meatier but no less accessible to the lay reader while at the same time enhanced in value to students of engineering.

I wish to thank all those people who have said kind things about the first edition, and especially those who have made helpful suggestions, some of whom may be able to detect traces of their advice in the new version.