The idea that an external force can enter an individual and possess their body is prevalent in most cultures across the globe and throughout history. This possession can last for varying lengths of time, and its effects can be considered positive--when a "spirit" provides the individual with powers, abilities, knowledge, or authority--or negative--when the individual suffers and the "spirit" should ideally be cast out, usually through a ritual performed by someone with a designated role. The study of possession remains marginal in most academic disciplines, but current public discourses indicate that the topic remains relevant across modern and postmodern societies. A globalized world has brought about an unprecedented situation in which decidedly different ideas about possession influence one another, and people attribute a wide variety of experiences and behaviors to spiritual possession. There are those who describe themselves as possessed, sometimes as an inherent element of their identities, and those who are labelled as possessed by others, though this label often comes with a stigma. Ideas of Possession brings together scholars of various disciplines to consolidate an ongoing academic discussion on how possession is understood within different cultural contexts. Essays present ideas of possession from Antiquity, Biblical Studies, Religious Studies, History, Ethnology, Anthropology, and Psychology, demonstrating how each field's approach to this subject can benefit from interdisciplinary dialogue as we attempt to make sense of such a broad range of interpretations.