Breastfeeding as a personal activity with health consequences is involved in a triangle of culture, health science, and fiscal economy. Epidemiology is a new science, scarcely a hundred years old, which arose out of studies of infectious disease epidemics and toxic-exposure cancer epidemics, and only recently has been used to investigate health behaviors and chronic diseases. The chapter discusses important issues from the vantage point of pediatrics and epidemiology. It examines the epidemiology and study design features of breastfeeding health benefit studies will be used to reflect on weaning studies. Health and business groups most able to generate immediate financial advantage from breastfeeding include capitated health insurance systems, such as Health Maintenance Organizations, and self-insured corporations. It appears to be imperative to include breastfeeding in national health policy consideration within industrialized nations. This is especially true for deliberations on health care reform within the United States.