I was thinking how when I was a teenager I was trying to find out what my values and beliefs were, and some of these cult books, though rather stupid and didactic, at least presented options. So although I wouldn't say I valued or liked all of them, I am not sorry I read them when I was 15 or 16. Even, let's say, Chariots of the Gods, or Casteneda, it's good to have read them.
Bold = have read - Almost all as a teenager.
Slaughterhouse-Five by Kurt Vonnegut (1969)*
The Alexandria Quartet by Lawrence Durrell (1957-60) (I've read one of these, didn't like it much)
A Rebours by JK Huysmans (1884)
Baby and Child Care by Dr Benjamin Spock (1946)
The Beauty Myth by Naomi Wolf (1991)
The Bell Jar by Sylvia Plath (1963)*
Catch-22 by Joseph Heller (1961)*
The Catcher in the Rye by JD Salinger (1951)
The Celestine Prophecy by James Redfield (1993)
The Dice Man by Luke Rhinehart (1971)
Chariots of the Gods: Was God An Astronaut? by Erich Von Däniken (1968)
A Confederacy of Dunces by John Kennedy Toole (1980)
Confessions by Jean-Jacques Rousseau (1782)
The Private Memoirs and Confessions of a Justified Sinner by James Hogg (1824)
Dianetics: the Modern Science of Mental Health by L Ron Hubbard (1950)
The Doors of Perception by Aldous Huxley (1954) *
Dune by Frank Herbert (1965)
The Hitchhiker's Guide to the Galaxy (1979) *
The Electric Kool-Aid Acid Test by Tom Wolfe (1968)
Fear of Flying by Erica Jong (1973)
The Female Eunuch by Germaine Greer (1970)*
The Fountainhead by Ayn Rand (1943)
Gödel, Escher, Bach: an Eternal Golden Braid by Douglas R Hofstadter (1979) *
Gravity's Rainbow by Thomas Pynchon (1973)*
The Holy Blood and the Holy Grail by Michael Baigent, Richard Leigh and Henry Lincoln (1982)
I Capture the Castle by Dodie Smith (1948)
If on a Winter’s Night a Traveller by Italo Calvino (1979) (not really my kind of thing, but well written)
Iron John: a Book About Men by Robert Bly (1990)
Jonathan Livingston Seagull by Richard Bach and Russell Munson (1970)
The Magus by John Fowles (1966)
Labyrinths by Jorge Luis Borges (1962) *
The Leopard by Giuseppe di Lampedusa (1958)
The Master and Margarita by Mikhail Bulgakov (1967)</b> (I want to read. H has it somewhere)
No Logo by Naomi Klein (2000)
On The Road by Jack Kerouac (1957)
Fear and Loathing in Las Vegas by Hunter S Thompson (1971)
The Outsider by Colin Wilson (1956)
The Prophet by Kahlil Gibran (1923)
The Ragged Trousered Philanthropists by Robert Tressell (1914) (not finished)
The Rubáiyát of Omar Khayyám tr by Edward FitzGerald (1859) *
The Road to Oxiana by Robert Byron (1937)
Siddhartha by Hermann Hesse (1922) (I think they should have chosen 'Steppenwolf')
The Sorrows of Young Werther by Johann Wolfgang von Goethe (1774)
Story of O by Pauline Réage (1954) I agree with the Telegraph: "Bewildering, creepy and joyless". Hated it.
The Stranger by Albert Camus (1942)
The Teachings of Don Juan: a Yaqui Way of Knowledge by Carlos Castaneda (1968)
Testament of Youth by Vera Brittain (1933)
Thus Spoke Zarathustra by Friedrich Wilhelm Nietzsche (1883-85) *
To Kill a Mockingbird by Harper Lee (1960)*
Zen and the Art of Motorcycle Maintenance: an Inquiry into Values by Robert M Pirsig (1974)
* I've put stars next to the ones I still think are good