This book argues that, because existence costs (the two words are cognates), any living thing must economize—shift more of its energy costs onto the world, including other living things, than its competitors are able to; that to economize is therefore to engage in exchanges that are sacrificial at their core; and that such economization is infanticidal in its ultimate implications. The opening chapters delineate the infanticidal ramifications of the central concepts of evolutionary biology (for example, the concepts of adaptation and reproductive fitness). Succeeding chapters show how texts foundational to western culture—Genesis, the Odyssey, Oedipus the King, the Gospel of John—have attempted to demystify the cultural practices that repress the recognition of the infanticidal horizon to biological existence. The final chapter shows how four contemporary American science fiction films (StarTrek: The Motion Picture, Terminator 2: Judgment Day, The Matrix, and Alien Resurrection) struggle against the infanticidal critique at work in the Judeo-Christian and Greek traditions.