For several years now, those working in public health have been building the case that climate change is a major public health issue. National Public Health Week 2008, themed “Climate Change: Our Health in the Balance,” was the official start to APHA’s work to illuminate the connection between climate change and public health. Working with our diverse partners across the country, APHA is educating national policymakers and practitioners about the vital role of public health agencies in addressing climate change and in preparing communities for related health impacts. Since then, much has been accomplished, but much remains to be done. At the federal level, the Centers for Disease Control and Prevention (CDC) has been instrumental in the public health response to climate change. CDC published a series of articles on climate change and public health in the November 2008 issue of the American Journal of Preventive Medicine and has established a climate change program to administer grants to help state and local health departments assess and build their capacity to address climate change.State and local health officials should participate in climate planning processes, conduct local needs assessments, monitor and prepare for current and future climate-related health risks and educate the public about health risks associated with climate change. To assist in this work, APHA, with funding from and in collaboration with CDC, hosted a year-long, six-part webinar series titled “Climate Change: Mastering the Public Health Role” in 2009–2010. More than 2,600 public health practitioners from across the country tuned in. APHA and CDC are pleased to present this guidebook as a “translation” of that webinar series. APHA and CDC will continue to collaborate with our partner organizations to supply additional guidance and information as it develops in the future. This is only the beginning — there is much more work to do. We hope you find this guidebook useful in shaping your public health response to the challenges of climate change program to administer grants to help state and local health departments assess and build their capacity to address climate change.