War unsettles ideas of human even as it encourages anthropocentrism. This transhistorical claim is at the heart of author's argument about war and ecology in early modern Englandan argument that is, in most other respects, historical. War reminds us, even when we'd rather not hear the news, that we are human-technology symbionts. From Desiderius Erasmus's contempt for "men of iron" amid the rise of cannons and firearms to the "never again" response to modern, industrialized warfare and our own Asimovian fears about robot warriors, new technologies of war have led to anxious interrogations of what it means to be human. By distributing agency into complex networks or assemblages of humans, animals, and objects, war makes confident assertions of human autonomy appear absurd. It is thus ironic that humans, who have long ignored most if not all nonhuman agents, are themselves unable to act in so many of the ways that matter. This chapter also presents an overview of the book.