The Golden Bough is an extensive comparative study of religion and mythology written by Scottish anthropologist Sir James George Frazier in 1890. The Golden Bough is historically significant in that it is one of the first works to view religion, especially Christianity, from a modernist rather than theological perspective, showing how Christian rituals such as Christmas are continuous with pagan festivals practiced for thousands of years before Christ. At over 800 pages, The Golden Bough is a tome, but it is considered one of the most important classics in cultural anthropology and the study of mythology and religion.
The Golden Bough begins by examining the succession rules of the priesthood at Nemi (near Rome), with the priest being ritually murdered by his successor. In trying to come up with a reasonable explanation for the origin of his succession rules, he examines a wider and wider sphere of world mythologies, examining customs from old England to those of the Australian aborigines. His eventual conclusion is that most, if not all, of the old religions were fertility cults that revolved around the worship and then the periodic sacrifice of an ancient king.
Aside from focusing on his central thesis, Frazier addresses many side points in The Golden Bough, exploring the fuzzy boundary between "sacred" and "unclean" known as "taboo," pointing to African tribes that change words in their language every week because they refuse to say any words that even resemble the names of their dead ancestors. He notes that many of the old gods, such as Dionysius, began by being represented exclusively in animals and only through cultural evolution became embodied as people. Many of the animals that originally represented these gods began to be ritually sacrificed to them.
Frazier looks into the historical obsession with crops, especially corn, and the complex rituals concerned in planting, harvesting, and consuming the crop. He looks at various "sympathetic magic" strategies used by our ancestors to promote the growth of crops, including but not limited to: human sacrifice, sexual intercourse at the instant of sowing the seed, mocking he who is last to reap the corn, idols made of the last bunch of corn to be reaped, etc. Some of these rituals have obvious connections to fertility rituals, but others are more obtuse and require some explanation and analysis. Frazier does an excellent job of this in The Golden Bough.