The public health system represents a wide variety of actors playing key roles in the ongoing script to improve the quality and quantity of life for the U.S. population. The specific parts that public health is being asked to play and the resources available to support its infrastructure for prevention and response to infectious diseases, chronic medical conditions, and disasters are discussed here in light of new national survey data from state and local jurisdictions. Although the public health system has both traditional and newly defined roles to play, resources,as measured by per capita spending and workforce availability,have not kept pace.[Health Affairs 25, no. 4 (2006): 911–922; 10.1377/hlthaff.25.4.911]