Three years have passed since the first edition of Basics of Environmental Science appeared. During this time new concerns have arisen, the controversy in Britain over the safety and desirability of genetically modified foods being the most spectacular example. At the same time, our understanding of other issues has improved as more information about them has been gathered.

Revising the book for its new edition has given me the opportunity to add more information where it is now available and to outline some of the new controversies, including that over genetically modified food. At the same time I have been able to study the whole of the text and to bring it up to date where necessary.