THE PLAGUE YEARS Mankind has always been fascinated by "origins," and biologists are no exception. Darwin is our most famous example. What is the origin of mankind, of species, of infectious diseases? In the last few years we have seen the emergence and spread of some apparently "new" viruses, such as HIV -1 and the virus causing bovine spongiform encephalomyelopathy. But are these, in fact, entirely new agents, or mutated forms of "old" viruses that have evolved along with us for eons? Edgar Hope-Simpson could not have written this book at a more opportune moment. He is a firm believer in...