Jonas Salk became a medical hero in 1955 for developing a vaccine that helped conquer polio. Salk grew up in New York City and earned a medical degree in 1939 from New York University. He then worked at the University of Michigan and the University of Pittsburgh, studying influenza and, during World War II, working on a flu vaccine for the U.S. Army. He began work on the problem of polio (at the time known as "infantile paralysis") in 1947, thanks in large part to the work of a Harvard group led by John Enders. (Enders had developed a way to grow the polio virus, which in turn allowed expanded research.) Many microbiologists were working on a vaccine, but Salk got there first. He began a program of experimental vaccines on humans in 1952, and by 1954 the vaccine was being prepared in quantity. The story became public in 1955 and Salk became a celebrity because of the success of the vaccine. A tireless champion of public health education and vaccinations, Salk became the director of the Salk Institute for Biological Studies in 1963, a post he held the rest of his career. He also authored several books, including Man Unfolding (1972), The Survival of the Wisest (1973) and Anatomy of Reality (1983).