Public health is the art and science of preventing disease, prolonging life, and promoting health through the organized efforts of society. The goal of public health is the biologic, physical, and mental well-being of all members of society. Thus unlike medicine, which focuses on the health of the individual patient, public health focuses on the health of the public in the aggregate. Public health professionals graduate can do work in biological sciences, technology, social sciences, and politics. Public health is a global issue, and will become even more so in the 21st century, as the interconnectedness of nations increases through modern communication, resulting in the need to deal with epidemics of communicable and non-communicable disease and environmental issues that require transnational solutions. Public health professionals will be required by nation to anticipate and prevent future problems, identify current problems, identify appropriate strategies to resolve these problems, implement these strategies, and finally, to evaluate their effectiveness.