This book consists of four parts. The first part, by Gabrielle Marceau, investigates the interface between the trade and climate change regimes. She focuses on the rules of the General Agreement on Tariffs and Trade (GATT) such as national treatment, most-favored-nation treatment, and Article XX exceptions addressing the interaction of these rules with greenhouse gas mitigation policies and measures. In addition to GATT, she also discusses the Agreement on Technical Barriers to Trade (TBT) and some WTO disciplines relevant to climate change policies.