THE ARCTIC is no longer the isolated, almost legendary part of the world that it once was. The military consequences of an atomic age, the press for natural resources, and the demands of international air travel bring increasing numbers of people to arctic and subarctic regions, with a consequent need for information on medical problems incident to life in cold climates (1). Epidemiological investigation in the arctic has a peculiar fascination; so little has been done that almost every observation is a contribution to knowledge. This satisfaction is tempered, however, by the realities of fieldwork in a physical environment demanding beyond most others. Hotels are not to be found in the far north; even a modest lodging house is rare; and the hospitality of what may be no more than a chance acquaintance becomes priceless. Travel is arduous. Long trips by commercial airline and local travel by boat, bush plane, and dog sled to collect information on a few hundred people are not unusual. A diet that includes whale meat and seal liver, although admittedly these are delicacies, still takes some accommodating. The intestinal infections are an attractive starting place in arctic epidemiology because the mass behavior of these diseases has been well worked out through long study in temperate and tropical regions. Also, the required bacteriological procedures are relatively simple, a consideration of moment in the arctic where field conditions are as difficult as they are. Alaska was chosen as the first study area. As a cultural and administrative part of the United States, conditions were good for communication and cooperation. The primary purpose was to determine under arctic conditions the mode of transmission of acute infectious diarrhea of man, and to learn something of prevalence and seasonal incidence. Also, intestinal parasites of dog and man were surveyed in two villages, and the ecology of fish tapeworm was examined in one area. Recurring outbreaks of enteric disease have been recorded among Eskimo populations of Alaska for at least a century and a half, along with dramatic epidemics of smallpox, measles, and influenza. In 1807, Unalaska was devastated by an epidemic, presumably of bacillary dysentery, and the Klondike gold rush of the late 19th century brought outbreaks of dysentery and typhoid fever (2). Salmonella typhosa and other salmonellae were isolated repeatedly after the first public health laboratory was established in 1936. Seventeen cases of typhoid fever occurred in Anchorage and its Dr. Gordon is professor of preventive medicine and epidemiology, and Dr. Babbott, formerly associate in epidemiology, Harvard School of Public Health, Boston, Mass., is now assistant professor of preventive medicine and epidemiology, University of Pennsylvania Medical School, Philadelphia. This .study was sponsored by the Commission on Environmental Hygiene, Armed Forces Epidemiological Board, and supported in part by the Office of the Surgeon General, Department of the Army, Washington, D. C.