In 1966, two authorities on LSD—Richard Alpert, PhD, AKA Ram Dass, and Sidney Cohen, MD—spoke out on the merits and dangers of the psychedelic drug as acclaimed photographer Lawrence Schiller documented the experiences as they were happening. This Commemorative Edition of LSD looks back at the public's use of LSD in the 1960s and features a new introduction that explores the book's relevance to today's psychedelic renaissance.