Oak is a Swedish progressive rock band that came into prominence in the mid-2010s. Their musical style is characterized by a blend of ambient electronic music, alternative rock, and folk. The band's line-up consists of Simen Valldal Johannessen, Øystein Sootholtet, and Sigbjørn Reiakvam, with Johannessen's emotive vocals and piano playing being a distinctive element of their sound. Their debut album, "Lighthouse", released in 2013, has been influential in the progressive rock scene, demonstrating their ability to weave intricate narratives with engaging musical compositions.