Conversation so far:
What year did Terence Mckenna begin doing public speaking?
In the early 1980s, Terence McKenna began to speak publicly
What did Terence Mckenna mainly speak about publicly?
Terence Mckenna spoke on the topic of psychedelic drugs, becoming one of the pioneers of the psychedelic movemen
Where did Terence Mckenna mostly give his speeches?
Did Terence Mckenna ever appear at any festivals or large scale events?
In 1994, Terence McKenna appeared as a speaker at the Starwood Festival, documented in the book Tripping by Charles Hayes
Did Terence Mckenna ever write any books or make a documentary?
Terence McKenna published several books in the early-to-mid-1990s including: The Archaic Revival; Food of the Gods; and True Hallucinations

Question: What was the subject of these books?
Self-contained rewrite: What was the subject of The Archaic Revival; Food of the Gods; and True Hallucinations published by terence Mckenna?