Therapies are potent. Their implications are literally life and death. Before a therapy touches a patient, and before a therapy can be sold on the open market, it must be approved by a regulatory body. The most important regulatory body in the world today is the US Food and Drug Administration (FDA). Every country has a regulatory body that performs similar functions, but few therapies are developed without the FDA in mind. We know the FDA better than any other regulatory agency and will therefore focus on it exclusively herein.