Transgenic cotton is now grown in a variety of countries especially the USA, Australia, and China. It is a focus of much of the environmental risk assessment work on genetically modified (GM) crops. This book provides a review of the biotechnology of cotton, and is an extension of a review article, published originally in 1991, following ten years of research and production experience in transgenic cotton. New topics have been added to reflect both the growth of research in this subject area and the issues and problems that have arisen as a result of transgenic cotton production.