The heavy, psychedelic acid rock of Iron Butterfly may seem dated to some today, but the group was one of the first hard rock bands to receive extensive radio airplay, and their best-known song, the 17-minute epic "In-A-Gadda-Da-Vida," established that more extended compositions were viable entries in the radio marketplace, paving the way for progressive AOR.

The track was written by vocalist, organist, and bandleader Doug Ingle, who formed the first incarnation of Iron Butterfly in 1966 in San Diego with drummer Ron Bushy. After the group moved to Los Angeles and played the club scene, they secured a recording contract and got national exposure through tours with the Doors and Jefferson Airplane. Following the release of their 1968 debut album, Heavy, original members Jerry Penrod (bass), Darryl DeLoach (vocals), and Danny Weis (guitar) left the band and were replaced by guitarist Erik Braunn and bassist Lee Dorman. Weis went on to join Rhinoceros. The new lineup recorded In-A-Gadda-Da-Vida later that year, which sold four million copies and spent over a year in the Top Ten. (The title has been translated as "In the Garden of Eden" or "In the Garden of Life.") A shortened version of the title track, which contained extended instrumental passages with loud guitars and classical/Eastern-influenced organ, plus a two-and-a-half-minute drum solo, reached number 30 on the singles charts.

The follow-up album, Ball, showed greater musical variety and went gold, but it also marked the beginning of the band's decline. Braunn left the group and was replaced by guitarists Mike Pinera and Larry Rhino Reinhardt, but the band's success was largely over. Iron Butterfly broke up in 1971; Braunn and Bushy re-formed the group in the mid-'70s without success. Drummer Ron Bushy died in Santa Monica, California on August 29, 2021, at the age of 79. ~ Steve Huey, Rovi