This document discusses core public health functions and essential public health services. It describes how public health aims to define and address the health of entire populations, rather than just individuals. Public health considers factors like behavior, environment, socioeconomics, and more that influence community health outcomes. It outlines how public health has helped extend average life expectancy by 25 years over the last century by preventing disease, promoting healthy behaviors, and assuring access to healthcare. The core functions of public health are described as assessment of community health needs, development of policies and education, and assurance of services.