Gene therapy has generated enormous expectations as it holds a great promise, namely to revolutionize clinical and molecular medicine. This is because the successful introduction of a gene sequence in somatic sells followed by long-term expression at therapeutic levels can fundamentally correct a variety of human disease such as inherited and acquired disorders, cancer and AIDS. The proceedings of the first ASI on Gene Therapy that took place from August 17-28, 1997 on the island of Spetsai, Greece, summarizes recent advances in the field as presented elegantly by the intemationally­ recognized experts that served as faculty at the meeting. Their contributions constitute brief but comprehensive reviews presented as independent chapters in this book and emphasize the influence of chromatin structure on gene expression, describe the principal mechanisms of gene expression, followed by articles on epigenic elements, viral vectors, non-viral vectors as gene delivery systems, animal models of human diseases, inducible regulatory systems, gene therapy of cancer, AIDS, monogenic disorders and ongoing clinical trials. Gene therapy is the logical progression to human health management because it offers a potential low cost and efficient treatment. Gene therapy can reach it's full potential and satisfy all expectations. However, a number of critical technology advancements need to be completed. These include the development of vectors capable of safe and efficient gene transfer, the control of cell type targeting and regulation of trans gene expression levels.