LSD
From dKosopedia
No examination of the 60s can be complete without acknowledging the profound effect that the large-scale unsanctioned experiments, starting in 1964, with this powerful perception-altering substance, had upon the creative processes of an entire generation.
Rather than explain that myself, I'll try to find some links by other observers that can back up so outrageous a statement. Seems pretty obvious to me, but it seems to be the fashion these days to dismiss as much of the sixties' profound influence upon the American Dreamstate as can be done. Acid changed everything; just ask the folks who were there.
External links
- Wikipedia: LSD