The possibility of treating cancer, a disease frequently defined by genetic defects, by introducing genes that target these very alterations has generated tremendous enthusiasm. This enthusiasm, however, has been tempered by an increasing number of obstacles to successful therapy, including vector systems that do not reach systemic metastases, therapeutic genes with redundant mechanisms allowing for cellular resistance, and toxicities in clinical trials that result in premature closure. The three comprehensive sections of this volume present currently available cancer gene therapy techniques, with specific attention to these trouble spots. Part I describes the various aspects of gene delivery including vehicles, or vectors, and their respective characteristics and production methods. In Part II, the contributors discuss strategies and targets for the treatment of cancer, including methods for cell-death therapies, correction of underlying genetic defects at the molecular level, and activation of the immune system or tumor microenvironment. The contributors provide a succinct framework for understanding the basic underlying oncogenic changes, which encourages the development of vectors engineered to exploit these gene mutations through selective spread of the vector in tumor cells with the specific changes. Finally, in Part III, experts in clinical gene therapy trials discuss the difficulties inherent in bringing gene therapy treatment for cancer to the clinic, and principal investigators present gene therapy approaches in the clinical testing stage and the results that have reached the stage ofclinical testing.of these trials.