Sidney Cohen was a Los Angeles-based psychiatrist. His work focused on the effects of psychedelics, primarily LSD. Cohen published 13 books in his life, all of them based on drugs and substance abuse. He began working with LSD in the 1950s. One of his earlier works is a video of an experiment that shows Cohen interviewing a woman before and after administering her LSD.
In the later part of the 1960s he worked as a director for the National Institute of Mental Health in their Division of Narcotic Addiction and Drug Abuse.  He has been open about having taken LSD many times himself, but was always opposed to the growing use of LSD amongst members of the counterculture movement. Cohen thought LSD was safe only if used under medical supervision and that the average person was not equipped with the ability to handle the drug safely. Through his work he had become known as one of the leading experts in LSD research.