In recent years, building on a new understanding of cellular biology and human genomics, gene therapy has emerged as a new potential treatment option for both monogenic and complex disorders. Currently, the most successful and researched gene therapeutic vector is the adeno-associated virus (AAV) due to many of its characteristics, which make it a safe and effective gene delivery system. However, one issue impeding its widespread clinical translation has been the extremely large dosages required for an effective therapeutic benefit. A consequence of the need for such high doses is the necessity for large production yields. If this obstacle can be overcome, the use of AAV for gene therapy will likely proceed at an unprecedented rate. This review discusses the use of AAV as a viral vector, including its clinical successes to date, its biology, vector design strategies, the costs and benefits of the most popular production techniques, and a brief discussion of purification strategies.