America north of the Rio Grande, that life zone sometimes referred to as the Nearctic region, presents the scholar of history and geography of disease with numerous challenges. These include such questions as the following: What potential disease-causing agents existed in the hemisphere before the comparatively recent arrival of human beings? How effective was the “cold screen” (Stewart 1960) in ensuring the health of the migrants crossing the link from Eurasia to the New World? Given the isolation of this population, how varied was it in a genetic sense, and how well adapted did it become to North American ecologies? Were native North Americans indeed “far more healthy than any others of whom we know” (Ashburn 1980)? Just what was the impact of the “Columbian exchange” (Crosby 1972)? Did these invaders receive the country “from the hands of nature pure and healthy” (Rush 1786)? What relative contribution to ill health and disease did the European group provide compared to that of the enslaved African populations? What were the dimensions and timing of the “epidemiologic transition” in North America (Omran 1977)? How real have urban and rural differences in health experience been through time? How serious is the threat today of “life-style” diseases?

Clearly all of these and other equally intriguing questions arise. This brief discussion can only hope to touch on some of them and to review a portion of the work by persons from biochemists to medical historians, from archaeologists to medical geographers, who have applied their learning to the fascinating question of human well-being through the ages in North America.