Knowledge is a hardcore punk song by the ska-core band Operation Ivy. It was written by lead vocalist Jesse Michaels and appeared on the album Energy. The song was covered by Green Day on their first album.
Knowledge is one of the more popular songs by Operation Ivy, and has been covered by many artists, including a notable cover by fellow Berkeley musical trio Green Day on 1,039/Smoothed Out Slappy Hours. When Green Day performs the song live, fans are invited to come onstage and play instruments. The Aquabats recorded a cover for the Operation Ivy tribute album Take Warning: Songs of Operation Ivy. A Millencolin cover of the song is available on their compilation The Melancholy Collection. Even in Blackouts recorded a version of the song for their album Myths & Imaginary Magicians.
In the opening of "Knowledge" at their last show at Gilman St.(this concert is the lint rides again bootleg) Jesse Michaels says, "This song is called Knowledge, and it's about growing up."