Experts broadly agree that stabilizing greenhouse gas (GHG) concentrations in the atmosphere to avoid dangerous GHG-induced climate change could be accomplished only with concerted efforts by all large emitting nations. Toward this purpose, delegations of 195 nations adopted the Paris Agreement (PA) on December 12, 2015. The PA outlines goals and a structure for international cooperation to slow climate change and mitigate its impacts over decades to come. This book is intended to answer some of the primary factual and policy questions about the PA and its implications for the United States.