The field of public health focuses on improving the health and wellness of populations, whereas the field of medicine aims to prevent, diagnose, and treat illness, one individual at a time. Thus, the field of public health is broad, with many sub-disciplines, discussed below. The Public Health Sciences major builds on connections between the liberal arts and the core concerns of public health, with the recognition that issues of human health are complex, influenced not only by human biology and statistics, but also by social structures, psychology,?culture, and public policy.