Book excerpt: This is the story of a killer that has been striking people down for thousands of years: tuberculosis. After centuries of ineffective treatments, the microorganism that causes TB was identified, and the cure was thought to be within reach--but drug-resistant varieties continue to plague and panic the human race. The "biography" of this deadly germ, an account of the diagnosis, treatment, and "cure" of the disease over time, and the social history of an illness that could strike anywhere but was most prevalent among the poor are woven together in an engrossing, carefully researched narrative. Bibliography, source notes, index.