The Golden Bough is an extermely ambitious attempt to devise a unified theory of all religion. Frazer uncovers the common magical basis of both "pagan" religions (consisting of multiple gods personifying different aspects of the natural world) and monotheistic ones. His basic thesis is that all religion is based on false beliefs about how nature works. Religious rituals are all geared towards magically strengthening the growth cycle of nature and inhibiting the death cycle. Different religions are simply different manifestations of this fundamental paradigm.
In making his point, Frazer gives an encyclopedic account of religious rituals and myths the world over. Even in this abridged version, he gives far too many examples. I felt a wave of relief every time he stopped giving examples and started actually speculating about their meaning. His speculations are indeed compelling, and his writing is often very eloquent, but this book is simply way too long. Don't feel guilty about skipping certain sections.
Frazer adopts an anthropological view of religion that is now called "intellectualism." It is the idea that religious concepts are the product of people's desire to *understand* how mysterious aspects of the world work. Indeed, Frazer argues that all religious rituals are predicated on implicit theories of how the world works and are attempts to influence that imagined world. His theory is interesting, but it is problematic. As Pascal Boyer points out in Religion Explained, the religious imagination is concerned only with particular mysteries; it is not concerned with other major questions, such as how thought magically produces physical movement (say, of one's arm) in the external world. This phenomenon is arguably far more complex and mysterious than the growth and death of plants. But this issue doesn't fascinate people and it isn't the focus of much religious thought. Why not? If we wish to understand religion, we must fundamentally explain why certain issues are central to the religious imagination while others are not. Intellectualism is hence an intrinsically flawed theory.
The Golden Bough nevertheless has much to offer. It includes provocative and seminal discussions of ritual, magic, animism, paganism, myth, and science. This particular abridgment is good because it includes Frazer's bold attempt to incorporate Christianity into his unified theory, thereby knocking it off its pretentious, fundamentalist pedestal (an attitude that permeated his society and surely agitated him). To debase Christianity was probably Frazer's ulterior motive in writing the Golden Bough, because his theory is actually more applicable to the crucifixion and resurrection of Christ than it is to many of the other religious systems he analyzes.
This book is worth reading for its historical significance, its ambition, and its enormous scope, but read it skeptically and be prepared to skip certain parts for the sake of your own sanity.