Causes of death varied systematically in the United States during the 20th century as the human environment came under control. Infections became less deadly, while heart disease grew dominant, followed by cancer. Logistic models of growth and multi-species competition in which the causes of death are the competitors describe precisely the evolutionary success of the killers. We show the dossiers of typhoid, diphtheria, cholera, tuberculosis, pneumonia/influenza, heart disease, cancer, and AIDS. Improvements in water and air supply and other aspects of the environment provided cardinal defenses against infection. We project cancer will overtake heart disease as the leading cause of death about 2015, and infections may gradually regain their deadly edge. © 2001 Elsevier Science Ltd. All rights reserved.