"Polio once frightened parents every summer. The disease could suddenly leave children paralyzed. But in the 1950s, scientists developed a vaccine that nearly eliminated the disease. Polio explores the history and science behind this disease, as well as how it's treated. Easy-to-read text, vivid images, and helpful back matter give readers a clear look at this subject. Features include a table of contents, infographics, a glossary, additional resources,...