This interdisciplinary study explores the relationship between conceptions of nature and (largely American) legal thought and practice. It focuses on the politics and pragmatics of nature talk as expressed in both extra-legal disputes and their transformation and translation into forms of legal discourse (tort, property, contract, administrative law, criminal law and constitutional law). Delaney begins by considering the pragmatics of nature in connection with the very idea of law and the practice of American legal theorization. He then traces a set of specific political-legal disputes and arguments. The set consists of a series of contexts and cases organized around a conventional distinction between 'external' and 'internal nature': forces of nature, endangered species, animal experiments, bestiality, reproductive technologies, genetic screening, biological defenses in criminal cases, and involuntary medication of inmates. He demonstrates throughout that nearly any construal of 'nature' entails an interpretation of what it is to be (distinctively) human.