"Know Your Enemy" is a song by the American punk rock band Green Day. It was released as the first single from their eighth album 21st Century Breakdown, through Reprise Records on April 16, 2009. Billboard described the song as being lyrically "just as politically charged as last time (on American Idiot)", having a "Modern Rock radio-ready chorus", whilst the song's producer Butch Vig "brings enough punk sheen for mass appeal." It was the first, and one of only three songs, to top the Rock Songs, Alternative Songs and Mainstream Rock Tracks Billboard charts at the same time. Know Your Enemy has been certified Gold by the RIAA and has sold 798,000 copies as of August 2010.