A theory of legal personhood Legal personhood is a foundational concept of Western legal thought. It has recently become highly topical underpinning contemporary debates over the legal status of animals corporations foetuses natural objects and artificial intelligences. The notion is furthermore crucial in explaining the historical legal statuses of women and slaves. Rather than addressing who or what should be a legal person this book examines the concept itself. The book consists of an Introduction and three parts. The Introduction presents the Western doctrine of legal personhood the relevant terms and concepts and the methodology employed in the book. Part I shows first how legal personhood came to be understood synonymously with the holding of legal rights and or duties. It then subjects this understanding of legal personhood to a rigorous scrutiny exposing numerous problems afflicting the view. Part II provides a completely new general theory of legal personhood arguing that legal personhood is best understood as a cluster property consisting of distinct incidents. The final part applies the new theory to explain and structure the numerous debates surrounding legal personhood explaining what is at stake in the animal legal personhood trials taking place in the US and elsewhere.