Medical Pioneer. He is universally known for his development of an effective vaccine for polio, a creation that has saved the lives of uncounted people since then. The first member of his family who went to college, he originally enrolled in the City College of New York to study law, but quickly came to change his field of study to medicine. While he was attending New York University's Medical School, he spent a year researching the influenza virus, which had just recently been discovered. He was fascinated by the research and wanted to see if the influenza virus might be deprived of the ability to infect people, while at the same time granting immunity against the virus. His theory was proven to be correct, and his research with influenza was to become the basis for his later work with the polio virus. He went back to researching influenza after finishing medical school and his internship. Since World War II had begun, many people were afraid that history might repeat itself and there would be another massive flu epidemic like there had been at the end of World War I. The influenza vaccines Salk helped to develop, at the behest of the United States Army, precluded another epidemic from happening. In 1947, he was offered the position of Director of the Virus Research Laboratory at the University of Pittsburgh's Medical School, and, while he was there, he worked with the National Foundation for Infantile Paralysis. He was inspired to develop a polio vaccine, something he worked on for the next eight years. On April 12, 1955, news of the vaccine and the successful trials performed on humans were made public, and Salk was hailed as a hero and miracle worker. For years, Americans had lived in fear of the polio virus, which had killed and crippled countless people, many of them children. Salk's reputation only increased when he refused to patent his vaccine. He wanted to make it available to as many people as possible, not to personally profit from this amazing medical breakthrough. His vaccine, which was administered by injection, contained "killed" polio virus, much like his influenza vaccine. The "killed" virus inoculated the patient without the risk of infection. A few years later, a new polio vaccine came out, but this vaccine was administered orally and contained a live polio virus. In spite of the great success of Salk's vaccine, there were many doctors and scientists who still believed that the best vaccine was made of toxoids (chemically treated toxins), and that immunity could not be acquired with a "killed" virus. Some patients caught polio after receiving this toxoid vaccine, and it was determined that Salk's vaccine was the superior one and the one that should be used. The countries that have used Salk's polio vaccine have virtually eradicated the disease. In 1963, with a twenty-million-dollar grant from the National Science Foundation and support from the March of Dimes, he founded the Jonas Salk Institute for Biological Studies, which conducts revolutionary scientific and medical research. Salk continued to conduct medical and scientific experiments, and published a number of books, some of them written with the help of his sons Jonathan, Darrell, and Peter, who had also become medical scientists. Among his books were "World Population and Human Values: A New Reality" (1981), "Anatomy of Reality" (1983), "The Survival of the Wisest" (1973), and "Man Unfolding" (1972). Salk's last years were spent researching the prevention of and possible vaccines against cancer and AIDS.