It is my solemn duty to present a list of books to do with altered, and altering, perceptions. It's traditional, when writing about this subject, to list books you'd like people to know you've read.
Take this quick-ish route to join in the fun: Hamlet's Mill, Passport to Magonia, On the Taboo Against Knowing Who You Are, Valis. The first two are grand, and accessible, works spanning all antiquity and myth. The latter two are contextual and exemplar texts on how real the self is.
Please do tell me which ones I've missed, and I'll tell you why I've not included them. Well-known titles could be omitted, but browsing around from known to unknown is much of the fun.
All titles are, at the time of writing, available at The Internet Archive, except * - and you can create a free account there, to borrow some of these and browse more. If you can spare it, please drop 'em a $ to keep it happening.
Adams, Douglas. 1979. The Hitchhiker’s Guide to the Galaxy.
Arendt, Hannah. 1951. The Origins of Totalitarianism.
ABible, The. 1611. (King James Version including apocrypha).
Bramley, William. 1993. The Gods of Eden.*
Bowart, Walter H. 1978. Operation Mind Control.
Carroll, Lewis. 1862. Alice’s Adventures in Wonderland.
de Santillana, Giorgio & Hertha von Dechend. 1969. Hamlet's Mill: An Essay Investigating the Origins of Human Knowledge and its Transmission Through Myth.
David-Neel, Alexandra. 1929. Magic and Mystery in Tibet.
Dick, PK. 1963. The Man in the High Castle.
Dick, PK. 1981. Valis.
Dr. Seuss. 1957. The Cat in the Hat.
Eliot, TS. 1922. The Waste Land.
Epic of Gilgamesh, The.
Forsyth, Frederick. 1971. The Day of the Jackal.
Gibson, William. 1984. Neuromancer
Grahame, Kenneth. 1908. Wind in the Willows.
Hall, Manly P. 1928. The Secret Teachings of All Ages.
Hancock, Graham. 1995. Fingerprints of the Gods: The Evidence of Earth's Lost Civilization.
Hebdige, Dick. 1979. Subculture: The Meaning of Style.
Heinlein, Robert A. 1961. Stranger in a Strange Land.
Hunkin, Tim. 1990. Almost Everything There is to Know.*
Huxley, Aldous. 1932. Brave New World.
Icke, David. 1996. I am me, I am free: The Robot's Guide to Freedom.
Koestler, Arthur. 1972. The Roots of Coincidence.
Lear, Edward. 1846. The Book of Nonsense.
Le Guin, Ursula K. 1968. A Wizard of Earthsea.*
Lovecraft, HP. 1936. At the Mountains of Madness.
Mack, Lorrie; Harwood, Eric & Riley, Lesley (eds). 1984. The Unexplained.*
Mackay, Charles. 1852. Memoirs of Extraordinary Popular Delusions and the Madness of Crowds.
Moore, Alan. 1982-88. V for Vendetta.
Orwell, G. 1948. 1984.
Sanderson, Ivan. 1974. Uninvited Visitors.
Sitchin, Zecharia. 1976. The 12th Planet.*
Vallée, Jacques. 1969. Passport to Magonia: from Folklore to Flying Saucers.
Upanishads.
Vonnegut Jr., Kurt. 1969. Slaughterhouse-Five.
Watts, Alan. 1969. The Book: On the Taboo Against Knowing Who You Are.
Webb, James. 1974. The Occult Underground.
Williamson, George Hunt. 1974. Secret Places of the Lion: Mysteries of Time & Space.
Wilson, Colin. 1971. The Occult.
Shea, Robert & Wilson, Robert Anton. 1975. The Illuminatus! Trilogy.