The Evolution of Religion (Barnes & Noble Digital Library)

This 1905 treatise, subtitled "An Anthropological Study," begins with a discussion of the discipline of comparative religion, then focuses specifically on rituals of purification, and, finally, on the evolution of prayer.  The author's aim throughout, as he puts it in his preface, is "to cool and temper the heated atmosphere of dogmatic controversy by presenting religious facts in their true proportion and proper setting."