Collected lectures on shamanism, multi-dimensional reality, time travel, voyaging beyond the ordinary, and exploration of expanded consciousness spaces.
I marked this as Buddhist because it's in the context of my Buddhist study that I read it, but it's not strictly Buddhist, while not strictly not. If you have the taste for this level of instruction it's a fantastic book. I read it years ago but understood a lot more this time around. It might help to Book 1, which is The Human Biological Machine as a Transformational Apparatus, first.
It's taking me through a journey beyond my physical body into a space unknown but so familiar. It's a book I'll be reading over and over again, because each time, there will be a new me so new things to learn.