On this day in 1966, Frank Zappa and the Mothers of Invention release their debut album, Freak Out!

The Mothers of Invention formed in California as the Soul Giants in 1964 with the line-up of Ray Collins, David Coronado, Ray Hunt, Roy Estrada and Jimmy Carl Black. In 1965, Frank Zappa was asked to take over as guitarist after Hunt was fired from the band, and he insisted they perform his original material, leading Coronado to leave the band as well. On Mothers Day of 1965, they changed their name to The Mothers, and after label executives demanded another change they became the Mothers of Invention.

After a string of successful shows in the LA underground scene, the group signed a deal with Jazz label Verve Records as part of the company’s plans to diversify into other genres. They started recording in March 1966 with producer Tom Wilson, who was already highly regarded thanks to his work with Bob Dylan and Simon and Garfunkel. The songs produced were very experimental, and heavily focused on Zappa’s satirical takes on pop culture and the so-called “freak scene” of LA. The recording continued for a month, and ran well over budget, costing MGM $25-35000 (equivalent to over $300,000 today).

Eventually, the album was completed, with so much material being recorded that it was necessary to release the project as a double album. This marked the first time a rock debut was released as a double, and only the second rock album ever to be a double, after Bob Dylan’s Blonde on Blonde a week earlier. Freak Out! is also often credited as being one of the first examples of a rock concept album.

The album released on June 27^th and made the band immediate darlings of the underground scene. However, Freak Out! only peaked at number 130 on the Billboard chart and was not popular amongst critics, with many criticising the album’s length and inherent “weirdness”. The band and Zappa himself soon earned themselves a cult following, along with the album, and their popularity only continued to grow throughout the 1960’s and 70’s. Critics eventually changed their tune as well, and Freak Out! came to earn itself a spot in the Grammy Hall of Fame in 1999, as well as being ranked at 243 on Rolling Stone’s list of “500 Greatest Albums of All Time.”