The idea of human gene therapy was accepted by the medical community and society at large long before believable clinical benefits began to emerge. In this book, some of the field's most distinguished contributors chronicle the evolution of this momentous direction for medicine, illustrating how imaginative concepts shaped the development of technologies and brought the daring new idea to its current position of imminent practical success. This is a book designed to endure as clinical advances accumulate, a clear-eyed work of reference that will anchor the further development of this revolution in therapy. It is an essential addition to libraries of clinical medicine, biotechnology, and public policy, and a resource that no laboratory investigator with an interest in the biology of gene transfer should be without.