The Golden Bough: A Study in Magic and Religion
I'm not going to embarrass myself by trying to write something insightful about this mighty tome, for one thing I haven't read it all. I prefer to dip in and read random bits when the mood takes me or use it as a reference for deciphering the occult activities that I occasionally encounter.
Like when my neighbours nailed a dead crow to my front door. Apparently it's not a good sign. I may well have been expelled from the circle.
But, yes, every home should have one, it's essential reading.