Big Brother and the Holding Company is an American rock band that formed in San Francisco in 1965 as part of the same psychedelic music scene that produced the Grateful Dead, Quicksilver Messenger Service, and Jefferson Airplane. After some initial personnel changes, the band became well known with the lineup of vocalist Janis Joplin, guitarists Sam Andrew and James Gurley, bassist Peter Albin, and drummer Dave Getz. Their second album Cheap Thrills, released in 1968, is considered one of the masterpieces of the psychedelic sound of San Francisco; it reached number one on the Billboard charts, and was ranked number 338 in Rolling Stone's the 500 greatest albums of all time. The album is also listed in the book 1001 Albums You Must Hear Before You Die.

The Acid Tests were a series of parties held by author Ken Kesey primarily in the San Francisco Bay Area during the mid-1960s, centered on the use of and advocacy for the psychedelic drug LSD, commonly known as "acid". LSD was not made illegal in California until October 6, 1966.