"Elementary Forms of Religious Life" is one of Emile Durkheim's most notable and complex pieces of writing. The article relates to the sociology of religion but also sets forth Durkheim's complex theory of human knowledge. According to Durkheim, at the basis of all religions, be it primitive or modern, stands the distinction between the sacred and profane (for a more detailed account see our summary of Durkheim's "The Sacred and the Profane"). For Durkheim the sacred is generated by means of rituals the created social cohesion and tie individuals to society. These bonds, which are articulated in moral terms, shape the categories through which we understand our social reality.
The differentiation between the sacred and profane takes shape not only in beliefs and rituals, but is also institutionalized in the structures of a church. This systemization of the distinction which forms "the elementary forms of religious life" is especially important for Durkheim since it is the rituals and churches which connect the individual to social structures. They are the source of knowledge regarding what is sacred and profane and the manners in which one should act to maintain this distinction. Durkheim gives the example of the Totem (elaborated in his The Genesis of the Totemic Principle of Mana) as a primitive form of such an organizing function. According to Durkheim the Totem is the material representation of the nonmaterial existence of the clan and its collective consciousness.
In summary, the key point in Durkheim's "Elementary Forms of Religious Life" is the relation he offers between social structure of religion and what can be described as ontological structure of reality itself. The form religion takes is the form of social life which echo in each other, correlating meaning and belief to law and order through rituals and religious institutions.
Durkheim's notions in "Elementary Forms of Religious Life" were later further developed by Mary Douglas in "Purity and Danger" and her notions regarding ritual uncleanness or secular defilement.