Underground is the second studio album by the American garage rock band, The Electric Prunes, and was released in 1967 on Reprise Records. It would be the final album of any materialized input by band members until the 1969 "New Improved" Electric Prunes were formed. The album was a moderate chart hit, but, without a hit-ready single, the band could not repeat their past success.
The album, Underground, brought changes to the band once recording began. Limited lyrical input plagued the band's creative process on their debut. Only one track, composed by Mark Tulin and James Lowe, called "Lovin'" was included on their first album. This changed with this album because Dave Hassinger, the group's producer, was not as active in the sessions resulting in nine of the 12 tracks becoming the band's own material. With so much more musical freedom, the band could mold their music into their own image. The final products were a more direct and cohesive set of songs that reflected the band's own design.
Transport's first two EPs and other songs including the single Sunday Driver were recorded by producer Guy Cooper on the Gold Coast.
The band has continued to record and perform independently of Kate Miller-Heidke, mainly at Brisbane venues but also on interstate tours and live radio broadcasts. The band's song Sunday Driver was downloaded a record 24,000 times from the website of youth radio network Triple J, and in Britain Stone Hearted has been aired on BBC Radio 1 and on Kerrang! Radio.