These are two different books: "Fear and Loathing in Las Vegas" by Hunter Thompson and "The Teachings of Don Juan" by Carlos Castaneda. Two completely different approaches to the perception of the world under the influence of psychotropic drugs. The first is just scary. The second is pure philosophy.
Read the books by Alexander Shulgin. A pharmacologist who has made a significant contribution to this field.
You can watch a film about his activities - "Dirty Pictures"
Timothy Leary is a classic of this theme. At one time, he began scientific research on psychedelics, defended their safety before Congress and gave up all scientific degrees in order to continue research. Reading, as for me, is very difficult. Probably due to translation and lack of deep knowledge in the history of the United States. For some reason, it is believed that in Russia it is difficult to find his books even in electronic form due to the fact that they reveal the terrible truth . But here's a link where there is even Neuropolitics: http://flibusta.is/a/7314
The coolest book on this topic, in my opinion, is "LSD - My Problem Child" by Albert Hofmann. It was this man who synthesized LSD and learned about its hallucinogenic effects by accident.