Pansychism is the idea that some form of mentality and consciousness exist in all living and nonliving things and thus presents a challenge to an unwavering physicalist metaphysics. The Routledge Handbook of Panpsychism covers the long history of the subject in philosophy--from the Presocractics to the 21st century--elucidates and synthesizes important contemporary philosophical and scientific research in the area, and addresses the advantages and difficulties of panpsychism as an approach to problems in philosophy of mind. With 30 chapters written especially for this volume by an internationally respected team of contributors, this Handbook serves as useful starting point and comprehensive reference for anyone interested in this promising, growing and multidimensional field.