This book examines the recent controversy between international trade and environmental policies. It analyses the use of environmentally-motivated trade policies, national environmental policies, and their relationships with the rules governing trade, critically examining proposals rule reform. A theoretical framework is provided for a consideration of the efficiency of environmental trade policies and an evaluation made of empirical links between environmental policy differences and trade flows. Concerns of developing countries over environmentally-motivated market access restrictions are highlighted in considering international trade rules and the agreements reached at UNCED.