1. Chapter 1: LSD

From its 1943 origins to today's microdosing trend, LSD has been expanding minds and changing lives with the help of counterculture gurus — and the CIA.

3. Chapter 3: MDMA

Championed by both therapists and ravers, ecstasy stands out as the first psychedelic likely to become legalized, thanks to passionate advocates.

4. Chapter 4: Mescaline

Mescaline, the psychoactive molecule in San Pedro and peyote cacti, a sacred medicine that Native Americans have had to fight for the right to use.