I'm currently reading this book called The Gates of the Necronomicon which is basically about magic and it sort of gives an interesting overview about things that ancient and not so ancient religions and/or mysticisms have in common. It is interesting to see how many of them seem to be based on learning how to do magic. And also that they are sort of interrelated, such as having gods or key figures that have very similar names and functions. Such as the Egyptian goddess Sheshat who, among other things, helped the builders to line up pyramids with the great celestial gate (called The Stretching of the Cord) which was the area of the heavens where, according to the ancient Indians and ancient Chinese, humanity came from. She, or at least someone who has a similar name, function and symbol (a seven pointed star on a pole) above her head, also shows up in other mysticisms.
Furthermore it tells about gates between our plane of existence and another plane. Which is the underworld or maybe just the spiritual world. If you gain access to this world you can learn the nature of magic or even achieve immortality. But it is dangerous to go there, you need to make sacrifices, you need to come apart or go insane (the destruction of the self) before you reach the end (where you are reborn). There is an interesting Sumerian story about the goddess Inanna, who descents unto the underworld and, during which, at each of the Seven Gates must remove a piece of clothing. She comes to the end of her journey naked..
O well, it's just interesting, that's what it is ;)