Totem and Taboo by Sigmund Freud

In this controversial study Sigmund Freud (1856-1939) applies the theories and evidence of his psychoanalytic investigations to the study of aboriginal peoples and, by extensions, to the earliest cultural stages of the human race before the rise of large-scale civilizations. Freud points out the striking parallels between the cultural practices of native tribal groups and the behavior patterns of neurotics. Beginning with a discussion of the incest taboo, he compares some of the elaborate taboo restrictions seen in these cultures to the scrupulous rituals of compulsion neurotics, who in a similar fashion are wrestling with the ambivalent emotions aroused by the incest taboo.
 He suggests that many of the rituals of culture are developed as psychological reactions to taboos, which prohibit the acting out of an infantile impulse that would be socially destructive.

Freud concludes by invoking his famous Oedipal complex as the key to the development of culture. The repressed psychological urge to kill the father as a rival for the mother's affections is the underlying motive for the symbols and ceremonies of religion with its rituals of atonement and its notions of angry gods, original sin, and human guilt.

Although Freud's theories are controversial today, this masterful synthesis and its undeniable influence on later scholars of religion, anthropology, and psychology make it a seminal work.