A renowned authority on diseases, presents a radical theory about the origin of deadly microbes in a book that takes us into the hot zones of today's most dangerous viral outbreaks, then into the research labs and hospitals where doctors and scientists are risking their lives trying to control them. AIDS, Ebola, mad cow disease, flesh-eating viruses...Today's newspapers are full of articles about new plagues and viruses. Where do these new viruses come from? Why do new plagues arise? Could there be -- will there be -- a lethal and incurable Virus X that spreads as easily as the common cold?