The human body has an impressive arsenal of defenses against pathogens, but bacteria and viruses are wily opponents, and tackling the most dangerous ones has become a battle of wits, one in which scientists have had both stunning successes and frustrating defeats. They must remain vigilant: Germs have plagued our species since its inception and they are here to stay. In this Scientific American anthology, prominent researchers and journalists discuss the new weapons of this war, such as virus-fighting drugs, edible vaccines and novel antibiotics; emerging enemies, such as anthrax and chronic wasting disease; and the all-too familiar foes HIV and hepatitis C.