Book excerpt: Muscle disease represents an important health threat to the general population. There is essentially no cure. Gene therapy holds great promise to correct the genetic defects and eventually achieve full recovery in these diseases. Significant progresses have been made in the field of muscle gene therapy over the last few years. The development of novel gene delivery vectors has substantially enhanced specificity and efficiency of muscle gene delivery. The new knowledge on the immune response to viral vectors has added new insight in overcoming the immune obstacles. Most importantly, the field has finally moved from small experimental animal models to human patients. This book will bring together the leaders in the field of muscle gene transfer to provide an updated overview on the progress of muscle gene therapy. It will also highlight important clinical applications of muscle gene therapy.