There is more to reality than meets a normal eye. Behind the curtain of everyday consciousness is hidden another unutterably strange universe.
It's the world of mystical experiences and those who have been there describe the visit as the most significant event in their lives.
Until recent times, it was a world known only to holy man, to saints, and perhaps to the insane. Then a generation ago, this drug, LSD, escaped from the laboratory and was consumed by millions of young people.
To some, it's a doorway to the mystical universe - chemical ecstasy, enlightenment in a bottle. To others it's a dangerous and subversive poison.
The drug challenges our very conception of reality and its' turbulent history raises sharp questions about the dividing line between private experience and public policy.