The Elementary Forms of the Religious Life by Emile Durkheim
In this work, first published in 1912, Emile Durkheim examines a wide range of religious topics including: forms of animism, naturism, and totemism; fundamental concepts such as the soul, spirits and gods; and cults and rites. He argues that the origins of religion are social in nature, and that religious forms cannot be understood apart from their functions.