Augustus Owsley Stanley III (January 19, 1935 – March 12, 2011) was an American-Australian audio engineer and clandestine chemist. He was a key figure in the San Francisco Bay Area hippie movementduring the 1960s and played a pivotal role in the decade’s counterculture. Under the professional name Bear, he was the sound engineer for the Grateful Dead, recording many of the band’s live performances. Stanley also developed the Grateful Dead’s Wall of Sound, one of the largest mobile sound reinforcement systems ever constructed. Stanley also helped Robert Thomas design the band’s trademark skull logo.

Called the Acid King by the media, Stanley was the first known private individual to manufacture mass quantities of LSD. By his own account, between 1965 and 1967, Stanley produced at least 500 grams of LSD, amounting to a little more than five million doses.

He died in a car accident in Australia (where he had taken citizenship in 1996) on March 12, 2011.

Stanley was the scion of a political family from Kentucky. His father was a government attorney. His paternal grandfather, Augustus Owsley Stanley, a member of the United States Senate after serving as Governor of Kentucky and in the U.S. House of Representatives, campaigned against Prohibition in the 1920s.