^Some gorillas don't like Timothy Leary!
It was unintended as
trip manual by Leary, Alpert and Metzner and was used as such by them in them sixties. It was based on the
Tibetan Book of the Dead. I used to have a copy called the
American Book of the Dead.
The Tibetan Book of the Dead is intended to be read to the dead as they are dying, I believe, but it's esoteric meaning supposedly is one of spiritual rebirth during life.