What is the importance of the notion 'human being'? The contributors to this collection have radically different approaches, some accepting and others denying its validity for a proper understanding of what a person is and for our ethical thought about each other. Contributors on both sides of the divide eloquently defend their views in ways that stand in sharp contrast to some current work in moral philosophy and philosophy of mind. Epistemological and theological issues are also raised in the provocative and wide-ranging discussions stimulated by the volume's theme.