The WTO, Animals and PPMs is a lucid analysis of the key difference between animal welfare protection and environmental protection of animals (biodiversity protection), providing a indispensable tool for distinguishing between the two. The comprehensive text centers on the barriers countries enact to protect animals in the course of trade. While the book utilizes examples of protection of endangered species and animal welfare issues, Dr. Nielsen’s WTO evaluation is applicable to a broader range of environmental and moral topics, none more so than her study’s focus on the GATT Article XX exception.

Dr. Nielsen’s framework for GATT Article XX consists of dividing the trade measures into three categories: internal, product related process and production methods (PR-PPMs) and non-product related process and production methods (NPR-PPMs). Via this approach she offers insight into issues such as sovereignty, policy direction, and analytical considerations regarding "nexus." Moreover, she offers analysis of the category of "morally"-motivated NPR-PPMs, which represents the biggest problem in the event of a WTO dispute. Her analysis of the TBT and SPS Agreements as well GSP schemes in the GATT Article XX context provide an even broader perspective and add multifarious layers to the discussion.

Over the course of her pointed work Dr. Nielsen shows the difference between animal welfare protection and environmental (biodiversity) protection of animals; provides a method for distinguishing between animal welfare and environmental protection; shows the legal obligations for states to protect animals; recommends ways for countries to ensure protection of animals located in other countries; and explains why, ultimately, it is important to distinguish clearly between "morals" and "science" in a WTO analysis of trade measures designed to protect animals - or humans.