Advances in genetics continue to be made at an ever increasing rate, which makes writing an introductory text somewhat difficult. In the few years since the first edition was published, many new applications of gene manipulation technology have been developed, covering a diverse range of disciplines. The temptation in preparing this second edition was to concentrate on the applications, and ignore the fundamental principles of the technology. However, I wished to retain many of the features of the first edition, in which a basic technical introduction to the subject was the main aim of the text. Thus some of the original methods used in gene manipulation have been kept as examples of how the technology developed, even though some of these have become little used or even obsolete. From the educational point of view, this should help the reader cope with more advanced information about the subject – a sound grasp of the basic principles is an important part of any introduction to genetic engineering. I have been gratified by the many positive comments about the first edition, and I hope that this new edition is as well received.

In trying to strike a balance between the methodology and the applications of gene manipulation, I have divided the text into three sections. Part I deals with basic molecular biology, Part II with the methods used to manipulate genes, and Part III with the applications.