The Golden Bough begins with a picture and a puzzle. At the woodland lake of Nemi in Italy stood the sanctuary of Diana of the Wood, guarded by a priest who paced the grove with a drawn sword. He held the title of King of the Wood, but he kept it only until a challenger broke a certain bough, fought him, and killed him. Frazer treats this strange and recurring tragedy as a survival from a far older world, and announces that the object of the book is to offer a probable explanation of it by tracing similar customs and the motives behind them across human society.
To explain the rite he first lays out the logic of magic. He argues that magic rests on two principles: that like produces like, and that things once in contact keep acting on each other at a distance. He names these the Law of Similarity and the Law of Contact, and groups the charms built on them as homoeopathic and contagious magic, together making up what he calls sympathetic magic. In his reading magic is a false science, a mistaken extension of the way ideas associate in the mind, which legitimately applied would yield real science instead.
From magic Frazer moves to kingship. The magician who claims to command rain and harvest can rise to become a chief, and then a man-god whose own body is believed to hold the welfare of the tribe. Such a figure is hedged with taboos that guard his precious life, yet the same belief turns lethal: if the course of nature depends on his vigour, his aging endangers everything. So divine kings were often put to death at the first signs of failing strength, sometimes after a set term, sometimes with a temporary substitute taking the blow, so that the indwelling soul could be handed on while still at its prime.
The middle of the book turns to gods who die and return. Frazer reads Osiris in Egypt, Tammuz and Adonis in Western Asia, and Attis in Phrygia as personifications of vegetation, deities who annually died and rose again. Their myths and rites, he argues, act out the decay of the year and its revival, and parallel customs surround the corn-spirit, the slain animal, and the human scapegoat who carries away the accumulated evils of the people. Across these chapters he assembles a vast comparative record of how communities have tried to kill off death and renew the life of the world.
At the end Frazer returns to Nemi to close the circle. He links the bough the challenger had to break with the mistletoe and with the myth of Balder, whose life lay hidden outside his body, so that the King of the Wood could not be slain until the bough was torn from the sacred oak. Stepping back, he offers his largest claim: that higher thought has moved on the whole from magic through religion to science, three threads he pictures woven into one changing web. Science is the best account so far, he writes, but not necessarily the last, and the book ends with the bells of Aricia ringing across the hills above the lake.