The African Muslim minority in Malawi has been identified with one particular linguistic group, the Yao. The dissertation begins with the problem of their conversion and adherence to Islam in the face of seemingly adverse circumstances. In exploring-solutions to this problem the emergence of a Yao identity is outlined and the politics of conversion are described. The narrative then moves on to the transformations of the Yao Muslims in the hundred years since their conversion. A model of religious change is developed that attempts to account for both the dynamics of change and the contemporary situation of Islam in southern Malawi. The Yao Muslims are shown to be divided into three competing and sometimes hostile factions that are termed the Sufis, the sukuti or 'quietist' movement and the new reformists. The appearance of these movements and their interaction with one another is described in relation to the questions of identity and religious practice. The model proposes a three phase scheme of Islamic change (appropriation and accommodation followed by internal reform and then the new reformist movement) that is defined in part by the relationship of the Yao Muslims to writing and the Book. It is suggested that a certain logic of transformation is endogenous to Islam as a religion of the Book and that the scripturalist tendencies of the reformist movement give it an advantage over the followers of Sufi practices, especially in the context of modern systems of communication and education. The general approach is that of an historical anthropology, linking notions of structured change to anthropological concerns with ritual and practice. The analysis concludes by raising questions about the nature of religious change in the context of an increasingly volatile world system and the place of the anthropology of religion in the understanding of modernity.