Comparative religion is the branch of the study of religions concerned with the systematic comparison of the doctrines and practices of the world's religions. In general the comparative study of religion yields a deeper understanding of the fundamental philosophical concerns of religion such as ethics, metaphysics, and the nature and form of salvation. Studying such material is meant to give one a richer and more sophisticated understanding of human beliefs and practices regarding the sacred, numinous, spiritual and divine.
In the field of comparative religion, a common geographical classification of the main world religions includes Middle Eastern religions (including Zoroastrism and Iranian religions), Indian religions, East Asian religions, African religions, American religions, Oceanic religions, and classical Hellenistic religions.
Nicholas de Lange, Professor of Hebrew and Jewish Studies at Cambridge University, says that
The comparative study of religions is an academic discipline which has been developed within Christian theology faculties, and it has a tendency to force widely differing phenomena into a kind of strait-jacket cut to a Christian pattern. The problem is not only that other 'religions' may have little or nothing to say about questions which are of burning importance for Christianity, but that they may not even see themselves as religions in precisely the same way in which Christianity sees itself as a religion.
According to Charles Joseph Adams, in the field of comparative religion, a common geographical classification discerns the main world religions as follows: