The Salk vaccine seemed like a miracle to parents whose children were threatened with the scourge of polio. With its protection from polio, came also a story line-there were heroic researchers who would use science to protect us from epidemics and perhaps even eradicate disease. For most people, vaccines have become the magic bullets for dealing with dangerous diseases. The continuing quest for new vaccines, including an HIV/AIDS vaccine, despite technical, epidemiological, and social obstacles, suggests the abiding power of this narrative. The author examines four cases that span the twentieth century--diphtheria, rubella, pertussis, and HIV/AIDS. Each case challenges the reader to examine how the values we attribute to vaccines influence their use. Diphtheria vaccination brought laboratory science into an existing narrative based on earlier vaccines. With rubella vaccine, researchers efficiently responded to an epidemic of birth defects while subtly changing the relationship between vaccination recipients and beneficiaries. Opposition to pertussis vaccine from average Americans created a narrative crisis, in which faith in vaccination as a whole seemed to be at risk. With more recent vaccines, including a hoped-for HIV/AIDS vaccine, the persistent cultural narrative continues to encourage vaccine development and use.