Incomplete coordination between medical care and public health delivery systems can result in significant missed opportunities for improving population health and constraining overall resource use. This lecture uses insight from the field of public health services and systems research (PHSSR) to examine: (1) why medical care and public health systems often fail to connect; (2) what are the potential health and economic consequences of these failures; and (3) what are the opportunities for connecting medical care and public health delivery to improve population health.