In this accessible primer, Dessler and Parson combine their expertise in atmospheric science and public policy to help scientists, policy makers, and the public sort through the conflicting claims in the climate-change debate. The authors explain how scientific and policy debates work, summarize present scientific knowledge and uncertainty about climate change, and discuss the available policy options. Along the way, they explain WHY the debate is so confusing. Anyone with an interest in how science is used in policy debates will find this discussion illuminating. The book requires no specialized knowledge, but is accessible to any college-educated general reader who wants to make more sense of the climate change debate. It can also be used as a textbook to explain the details of the climate-change debate, or as a resource for science students or working scientists, to explain how science is used in policy debates.