Jonas Salk became a hero after he developed the first vaccine to fight the polio virus. The summer of 1952 was the worst polio epidemic ever-nearly 58,000 cases were reported, and more than 3,000 children died. So when Dr. Salk was ready to test his vaccine in 1954, parents eagerly volunteered their children for the study. Salk tested the vaccine on more than 1.8 million children. More than a year later, he shared his good news. On April 12, 1955, Dr. Salk declared: "The vaccine works " Originally published in 1960 in author John Rowland's larger "The Polio Man: The Story of Dr. Jonas Salk," this Kindle edition describes, in simple language for young and old, how Dr. Salk developed a vaccine made from a dead polio virus that had been killed with formaldehyde; when injected, the vaccine fooled the body into producing protective antibodies that would fight a real polio invasion.