Gene therapy holds the promise of finding cures to some of the most problematic diseases. Unlike commonly used small molecule drugs, genes expressed in the body can perform more complex tasks and be better targeted to disease sites. In this course we will cover topics ranging from the need for gene therapy, through biochemical and device-based methods of gene delivery, to challenges facing current therapies. We will finish the course with case studies of successful gene therapies that are already on the market, and examine why gene therapies of the previous decades had limited success.