Many diseases are caused by a simple point mutation - they are the result of a single defective gene. Gene therapy is the attempt to replace a defective gene with a good copy or to add a good gene to compensate for the bad. Although this procedure has proven to be extremely hazardous, of all the technologies provided by the new biology, gene therapy holds much potential for curing disease. Dealing with one of the most controversial aspects of the new biology, Gene Therapy explores the development and future of this area of research and explains why it is considered such a promising branch of science. This encyclopedia presents an overview of genetic defects, viruses, and gene therapy in a way that students and general readers will find easy to understand. Comprehensive in scope, this book provides an account of the research leading to the first successful gene therapy trial and discusses the worldwide attention and subsequent controversy caused by the tragic death of a patient receiving gene therapy, as well as the future prospects and general ethics of gene therapy. Biographies of influential researchers in this field, a list of further reading, a glossary, and an index round out this timely reference.