Revolution is the second full-length album by the South Korean pop girl group Kara. It was released on online music sites on July 30, 2009, with a physical release on July 31. The album was the band's first regular release to be recorded under the second line-up, featuring members Goo Hara and Kang Jiyoung, who replaced Kim Sunghee after her withdrawal in 2008.

The lead single "Wanna" was released on July 28, 2009, ahead of the album's official release. The music video was released on July 29, with the full album being available on July 30. Promotional activities commenced on July 31, beginning with KBS's Music Bank; the group performed both "Wanna" and "Mister". After their performance aired, "Mister" proved to be popular with viewers due to a "butt dance" that is featured prominently in the choreography.

On August 30, 2009, "Wanna" won the "Mutizen Song" award from SBS's Inkigayo music program.

Due to the overwhelming response that "Mister" received, Kara's overall popularity increased, with numerous advertisement requests coming in for the group; they had more advertisements in October 2009 than the previous two years.

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