Gene therapy has been extensively researched in this all-inclusive book. Gene therapy as a field has gained its due regard after all these years of poor outcomes. Issues in the past which were troubling scientists and practitioners are now being easily resolved. The growth of secure and effective gene transfer and development in the field of cell therapy has now brought new ways to deal with varied diseases. The book aims at compiling information from different resources about various gene therapy tools, practical achievements of gene therapy and its future usage. Some of the important chapters discuss non-viral delivery systems in gene therapy, transgene expression, plasmid transgene expression in vivo - promoter and tissue variables, DNA electrotransfer as an effective tool for gene therapy, siRNA and gene formulation.