New biotechnologies have propelled the question of what it means to be human, or posthuman, to the forefront of societal and scientific consideration. This volume provides an accessible, critical overview of the main approaches in the debate on posthumanism, and argues that they do not adequately address the question of what it means to be human in an age of biotechnology. It offers a comprehensive mapping of posthumanist discourse divided into four broad approaches, two of them humanist-based approaches: dystopic and liberal posthumanism, and two non-humanist approaches: radical and methodological posthumanism. The author compares and contrasts these models through an exploration of key issues, from human enhancement, to eugenics, to new configurations of biopower, questioning what role technology plays in defining the boundaries of the human. Building on the contributions and limitations of radical and methodological posthumanism, the author develops a novel perspective, mediated posthumanism, that brings together insights into the philosophy of technology, the sociology of biomedicine, and Michel Foucault's work on ethical subject constitution. In this framework, technology is neither a neutral tool nor a force that alienates humanity from itself, but something that is always already part of the experience of being human, and subjectivity is viewed as an emergent property that is constantly being shaped and transformed by its engagements with biotechnologies. Mediated posthumanism becomes a tool for identifying novel ethical modes of human experience that are richer and more multifaceted than allowed by current posthumanist perspectives. This is an essential reading for students and scholars working on ethics and technology, philosophy of technology, poststructuralism, technology and the body, and medical ethics.