It is the virus hunters who are leading the life-and-death battles against viruses. Ken Stedman hunts extreme viruses that live in the boiling acid pools of Lassen Volcanic National Park in California. Donald Henderson is responsible for wiping out smallpox-the only virus that humanity has conquered. Within a year of its eradication, AIDS emerged to become a worldwide pandemic. Ebola, Marburg, SARS, West Nile Virus, and a host of new infectious diseases soon followed. Also explores such chronic diseases as cancer, heart disease, multiple sclerosis, and mental illness, which are now suspected of being caused by viruses. Even autism is suspected of being caused by an infection during pregnancy.