
The use of hallucinogenic plants has been a part of human experience for millennia, yet modern Western societies have only recently become aware of the significance that these plants have had in shaping the history of diverse cultures. Capable of bringing human beings in closer touch with the spirit worlds, hallucinogenic plants have long been venerated as aids to mental health and as the sacred connection to the mystical. The authors of this definitive book examine the cross-cultural ceremonial and ritual use of many hallucinogenic substances. Profusely illustrated, this book contains an extensively researched plant lexicon, providing common and botanical names, history, ethnography, preparation, chemical components, usage in healing, and effects for 91 hallucinogenic plants.
Plants of the Gods: Their Sacred, Healing, and Hallucinogenic Powers by Richard Evans Schultes (Author), Albert Hofmann (Author), Christian Rätsch (Author)
https://www.goodreads.com/en/book/show/580859
For a broader overview of the global history of psychedelics, "Plants of the Gods" by Schultes, Hofmann, and Ratsch:
https://www.amazon.com/Plants-Gods-Sacred-Healing-Hallucinog...
Fundamentally, I'd say psychedelics explicitly reveal that our sensory-informated reality is really just a somewhat fickle map of reality. This is particularly seen in the visual field, where images from memory can get fed back into normal sensory processing. One of the more accurate pop-culture references to what this is like was seen in this image from the first "Matrix" movie:
https://i.stack.imgur.com/zymAc.gif
Under higher doses one can completely lose grasp of visual perception (a rather dangerous state to be in if one is around say, high cliffs etc., which accounts for all the cautionary advice about safe settings and so on) but in this sort of intermediate state one can still navigate using one's sensory-supplied map of reality, but it really is just a map, and we are really in a similar position to that of a blind person using echolocation to find their way around. That's the 'great insight' of psychedelics IMO (which also makes psychedelics an incredible aid for 3D visualization in the arts and sciences, I think).
They can, however, also be emotionally and psychologically disturbing (fear, panic, paranoia, etc. are not unheard of responses).
Have you ever seen those movies where UN-connected people being connected at the end?
"Enter The Void" by the director Gaspar Noe brings you an ancient idea or theory of how is death after live and the circle of life like Tibetans see, and one or maybe the most close-to-reality theories of death. At the beginning and before the chaos start (no important spoilers), a third actor says whats gonna happen in the all movie just by describing a resume of the book "The Tibetan Book of The Death" and this give you some interesting toughs about how para-psychology works. http://archiwum.radionafali.com/books/The%20Tibetan%20Book%2... [The book translated]
Shamanic drugs like Ayahuasca and magic-shrooms are really a powerful guide with to understand how life works, "para-psychology" after that seems like a fancy word to something too normal. Give a quick 30min read to this, the culture reading are so marvelously interesting... https://archive.org/details/SchultesHofmannPlantsOfTheGodsHe... [Schultes, Hofmann (the same as the bike LSD squares!) "Plants Of The Gods"]
[!] You don't have to use drugs, drugs are so magical but so special and hard to control that you can have a really happy and wise life without them and just by informing yourself and open your mind every day a little more. (everything can be real.. )
Out there are more theories, the matrix, solipsism, you been your own good and everything is a reaction of your-self, etc.
what you're looking for are so beautiful, but be humble with the knowledge and careful.
The Psychedelics Experience by Peter Stafford
Pikhal by Alexander Shulgin
Acid Dreams by Lee and Shlain
The Illuminatus Trilogy by Shea and Wilson
Plants of the Gods by Richard Evans Schultes
The Archaic Revival by Terrence McKenna
The Psychedelic Explorer's Guide by James Fadiman
That should get you started. Good luck, and have a safe trip.