Charles Milles Manson (né Maddox; November 12, 1934 – November 19, 2017) was an American criminal and musician who led the Manson Family, a cult based in California, in the late 1960s. Some of the members committed a series of nine murders at four locations in July and August 1969. In 1971, Manson was convicted of first-degree murder and conspiracy to commit murder for the deaths of seven people, including the film actress Sharon Tate. The prosecution contended that, while Manson never directly ordered the murders, his ideology constituted an overt act of conspiracy.

Before the murders, Manson had spent more than half of his life in correctional institutions. While gathering his cult following, Manson was a singer-songwriter on the fringe of the Los Angeles music industry, chiefly through a chance association with Dennis Wilson of the Beach Boys, who introduced Manson to record producer Terry Melcher. In 1968, the Beach Boys recorded Manson's song "Cease to Exist", renamed "Never Learn Not to Love" as a single B-side, but without a credit to Manson. Afterward, Manson attempted to secure a record contract through Melcher, but was unsuccessful.

Manson would often talk about the Beatles, including their eponymous 1968 album. According to Los Angeles County District Attorney, Vincent Bugliosi, Manson felt guided by his interpretation of the Beatles' lyrics and adopted the term "Helter Skelter" to describe an impending apocalyptic race war. During his trial, Bugliosi argued that Manson had intended to start a race war, although Manson and others disputed this. Contemporary interviews and trial witness testimony insisted that the Tate–LaBianca murders were copycat crimes intended to exonerate Manson's friend Bobby Beausoleil. Manson himself denied having instructed anyone to murder anyone.