NPR PPMs are process and production methods that do not affect the product as such, meaning that there is no discernible difference in two products with different NPR PPMs. This work examines WTO states’ attempts to regulate in this regard and create product distinctions on the basis of NPR PPMs. To do so, it scrutinizes historical, institutional, substantive and case-law issues related to NPR PPMs, environmental policy and the WTO. Further, the book addresses the issues of legitimacy, regulatory space and reform, contributing to thelively debate on the future of the WTO.