Tropical medicine is outside the mainstream of biomedical research in America. Yet, worldwide, malaria continues to ravage millions, causing between one and two million deaths every year. And malaria at least is a household word. Not so kala azar, Mogul words that mean ``black sickness,'' a parasitic disease of the liver and spleen that causes fever and anemia and commonly proceeds to wasting, dysentery, and death. The record suggests that kala azar was a new disease a century ago--a sort of 19th-century AIDS that hit southeast India in epidemic proportions. It now occurs across China, Russian Turkestan, Mediterranean Europe, North Africa, and the coast of Brazil, with little in the way of treatment except for derivatives of the heavy metal antimony--in short supply and too expensive for the poor. Here, as in his other popular books (The Thorn in the Starfish, 1987, etc.), our tropical medicine man on the scene tells a compelling tale that is half epidemiological sleuthing, half an account of where we stand today. As always, too, there is a mixture of wordplay, compassion, and anger to suit the unfolding of tales that have comic as well as tragic turns and events that reveal heroism but also stupidity and cupidity. In the case of kala azar, we learn that the parasite is leishmania donovani--a protozoan transmitted by the bite of a sandfly. Prevention is plagued by politics as well as by lack of funding and ideas. Desowitz summarizes the details of the better--known malaria story, ending with a sizzling indictment of the Agency for International Development, complete with corrupt officials and venal researchers who pocketed funds awarded for vaccine research. Sad tales, these, that leave the reader with more respect for nature, less for man.