In the seventies I read a book that blew my mind. Here's what I remember of the plot: the first page is a warning of penalty from a galactic authority offering the threat of being nullification for revealing the attached contents.
What follows is an expose that combined the theories of reincarnation, god and the devil. Basically, the Earth is a type of penal institution, and we are beings controlled into believing that we are individuals but our existence/life is merely us serving our punishment sentence.
Also that there is no such thing as a good life or bad life, just how we choose to live that time period and its outcome either adds or detracts from our sentence. God and the Devil are merely incarnations of the beings who are the jailers. Have tried to remember the title but just can't, no pun intended.