This essay is a revision of my earlier effort to overturn the prevailing view that there is merely a ‘family resemblance’ between religions. A religion is a system of practices rationalized by beliefs according to which the practices place the practitioner in a relation-of-value to a supermundane reality so grand that it can figure centrally in the satisfaction of substantial human needs. A ‘supermundane reality’ is one that exceeds the mundane world revealed by sense perception. The theory generates a useful taxonomy of practices and theories closely related to, but substantially different from, religions.