The recent deaths from avian influenza in Vietnam, Cambodia, and Thailand have generated much concern that avian flu could be the world’s next great pandemic. As of this writing, forty-eight people have died and tens of millions of birds have been slaughtered. Microbiologists fear that if the current strain, which has been passed from bird to bird and from bird to human, were to evolve to allow human to human passage, it could quickly kill millions. What does this mean for our faith in modern medicine? Gerald Grob’s expansive history, spanning the centuries from colonial America to the present, seems ever more relevant as we contemplate this latest epidemiological threat. Grob shatters the comfortable assumption that the future of medicine is one of unlimited progress. Documenting the experience of disease in America, from smallpox to AIDS, he explores the many variables that have shaped epidemics and the role of medicine in containing them. After presenting extensive and detailed evidence, he argues that increased natural immunity, reduced pathogen virulence, improvements in nutrition, and broad public health policies have been much more important influences on declining mortality from infectious diseases than have medical discoveries or treatments. The continuing belief that medicine has played a larger role, and that further progress is inevitable and infinite, provides a false sense of security and may have had a deleterious effect on the design of research studies, funding allocations, and environmental and occupational health policy. As Grob concludes, “the faith that disease can be completely conquered is at best a harmless and at worst a dangerous utopian illusion” (p. 274). Beginning with the early colonization of America, Grob focuses on the major threats to health in each era for different groups of the population. Class, race, and gender are not central categories of his analysis; instead he concentrates attention on the biological “realities” of specific diseases and the population factors that nurture their spread. In meticulous detail, using a vast array of examples from across the country, he documents the terrible toll of contagious diseases on America’s indigenous Indian populations and the early colonists. He clearly establishes the role of previous exposure in creating immunity, as well as the broad array of variables that influence the impact of epidemics—so that the same disease has had different effects in various geographic locations and social environments and on older or younger populations. Grob then turns to the major epidemiological shift of the late nineteenth and early twentieth centuries, in which chronic illnesses overtook infectious diseases as the strongest driver of the country’s mortality rates. He explores various explanations for the declining significance of infectious diseases and draws particular attention to the epidemics of ill