Using a straightforward systems approach, Public Health: What It Is and How It Works explores the inner workings of the complex, modern U.S. public health system—what it is, what it does, how it works, and why it is important. The book covers the origins and development of the modern pubic health system; the relationship of public health to the overall health system; how the system is organized at the federal, state, and local levels; its core functions and how well these are currently being addressed; evidence-based practice and an approach to program planning and evaluation for public health interventions; public health activities such as epidemiological investigation, biomedical research, environmental assessment, policy development, and more. Updated and New Information in the Fifth Edition: • NACCHO Profile data from 2008 and 2010 surveys • Accreditation of public health agencies • Public health workforce development activities including the credentialing of public health workers • Health reform provisions enacted in 2010 • Updated and revised section on public health financing