This book is about transgenic animals--animals into which new genes have been artificially introduced. It has chapters by leading authorities on the present state-of-play regarding the application of the transgenic technology to different animal groups. Scientists have conducted experiments on a great range of animal types, ranging from protozoan cells, through nematode worms and fruit flies to many higher vertebrates, and this book provides an in-depth, up-to-date, comprehensive and authoritative account of the work with all such animal types. The likely impact of transgenic animals on the future of agriculture and medicine is very great. These animals provide an unrivaled experimental system for the study of gene regulation, genetic aspects of disease, and gene therapy. One of the objectives of the book is therefore to set transgenic animals in the context of their present and future contributions to science and medicine.