The author explores the nature of theory and provides an overview of resources for the study of conversion to Islam. Theory is valuable in so far as it illuminates different aspects of a phenomenon. Various theoretical approaches include some dimensions and exclude others. Scholars of conversion must be aware of theoretical issues and systematically utilize theoretical options with sophistication. Such an approach will expand understanding of conversion and also enhance comparative studies of conversion. Theoretical orientations considered in this paper include: globalization, post-colonial, feminist, cross-cultural, religious/spiritual, intellectualist, narrative, identity, ritual, psychoanalytic, archetypal, attribution, attachment, process/stage, and Islamization theory.