The paper is a phenomenological study of spirit possession in an East African Muslim context, and based on ethnographic field work, the main method in the field of sociocultural anthropology. It argues that unreciprocated love is a popular reason for spirit possession in East Africa because of the East African concept of personhood which is radically different to Biblical conceptions, and also makes significant adaptations to Islamic notions of personhood. The first part shows that African personhood, Biblical personhood, and East African personhood have ontological and normative aspects. The second part outlines East African cosmology and presents an extended case study on spirit possession. The argument is made that East Africans conceptualise jinn as persons who live lives that parallel the lives of human individuals and societies, while representing an evil opposite. The specific jinn category qareen, it is argued, should be included in the definition of East African human personhood, as qareen are semi-autonomous extensions of human persons. A human person, through their qareen, can enter another human person and take control of them. This possession is usually caused by love or envy. East African personhood, therefore, is contested and needs to be defended by acting according to local Islamic lifestyle principles. In the final part of the paper, it is shown that the East African concept of qareen has no equivalent in the Biblical concept of personhood. However, East African ‘jinnology’, despite certain significant differences, relates to Biblical demonology in that evil jinn fit into the category of unclean spirits.