Six boys playing by their homes near a forest along the Connecticut River come down with arthritis within a few months of each other. Young women in New Mexico report severe muscle pains, fatigue, skin rashes, and neurologic symptoms. Seven hundred men slowly suffocate soon after digging a tunnel in West Virginia. Young black men in the United States die of homicide more often than of any other cause. Women in the United States are much more likely than women elsewhere to have hysterectomy.

Why were these specific persons affected at those times and in those places? Were these new diseases? Old diseases in new settings? New exposures that cause disease? How epidemiologists have answered questions like these is the subject of this book.

The authors, themselves epidemiologists, describe how epidemiologists investigate disease patterns in populations. Like Berton Roueche, the authors tell the story of epidemiology, not by giving a stale description of its methods but by recounting its history. Both familiar forebears and lesser-known "epidemiologists" have their stories here: John Snow, who showed how water could transmit cholera before Vibrio cholerae was discovered; Joseph Goldberger, who proved that dietary deficiency rather than infection causes pellagra; Florence Nightingale, who described causes of death and evaluated health services in the British army; and Frederick L. Hoffman, a statistician for the Prudential Life Insurance Company, who identified dust as a cause of lung disease in miners.

The book shows how epidemiology has changed as its emphasis has changed from infectious to chronic diseases, from single agents to multiple risk factors, and from eliminating exposures to reducing them to safe levels. The authors convincingly argue that studying the health care system and the problems caused by newly emerging infections, overpopulation, and societal stresses will keep epidemiologists busy for quite some time.

Many clear pictures, tables, and even a "blues" song well illustrate the authors' conclusions. The book simplifies history somewhat by downplaying some controversies in epidemiology, such as why Snow's contemporaries ignored his conclusions. It exaggerates by stating that the work of epidemiologists accounts for "most of what is currently known about both the cause and prevention of human disease." It sometimes uses technical terms (age-adjusted, incidence) without defining them. An occasional fact is incorrect: Veins do not "lead to" the brain or other organs, and trypanosomes are not malarial parasites.

Despite these minor faults, the authors succeed in conveying the excitement and challenge of an important science.