This chapter addresses how polio was first discovered and then controlled, the problems with its elimination, and the argument for continued vaccination to ensure control. Polio was not defined as a specific disease entity until the late seventeenth century. Meanwhile, paralytic poliomyelitis epidemics first became known in the nineteenth century. Whether or not sporadic outbreaks of paralytic poliomyelitis occurred earlier is less certain and a matter of disagreement. The chapter then looks at the three main personalities who were fundamental in developing the vaccine for poliomyelitis: Jonas Salk, Albert Sabin, and Hilary Koprowski. Jonas Salk and his colleagues chemically inactivated the poliomyelitis virus with formaldehyde and provided a vaccine that produced immunity and dramatically lowered the incidence of poliomyelitis. However, this immunity waned over time. Additionally, administration by needle made vaccinations of large populations difficult. For these and other reasons, Koprowski, Sabin, and others independently worked on the development of a vaccine with live attenuated viruses. Without such combined efforts, the vaccine would never have materialized.