Essay I: LSD and the Search for the Philosopher's Stone. This essay was delivered as a commemorative speech for the hundredth birthday of Albert Hofmann. The discoverer of LSD, as the author illustrates in a fascinating historical retrospective from the earliest high cultures to modern times, belongs to the great tradition of alchemical natural philosophers who sought a holistic union of spiritual and material truth in their quest for the Philosopher's Stone.

Essay II: Expansions of Collective Consciousness. The introduction of psychedelic substances into secular culture in the mid-twentieth century represents a profound upheaval in the collective psyche of humanity. The socio-cultural transformations that emerged from this can be seen as a response of the collective psyche to the unprecedented threats facing modern civilization: nuclear war, U.