published. Indeed, most books in the field are either a collection of gene transfer laboratory protocols or deal with the subject in a rather superficial manner. Hence the idea to write a gene therapy textbook that is broad and comprehensive, but at the same time provides sufficient molecular and clinical detail to be of interest to students, professors, and specialists in the various disciplines that contribute to gene therapy. I have tried to keep the language plain and, whenever possible, non- technical. Since the book is intended to be a textbook in the field of gene therapy in both the basic science and clinical areas, whenever technical descriptions are required, they are provided.