"Bilateral" is the second studio album released by the Norwegian progressive metal band, Leprous. It was recorded in Ivory Shoulder Studios and Juke Joint Studio by Vegard Tveitan and Heidi Solberg Tveitan, and mixed and mastered at Fascination Street Studio by Jens Bogren. Additional editing by Ivar Barstad. The music is arranged by the whole band and the lyrics are the work of Einar Solberg, Øystein Landsverk and Tor Oddmund Suhrke. Art direction and design by Ritxi Ostáriz. Cover painting by Jeff Jordan. All songs published by Magic Art Publishing. In order to define the band's vision about music and what it means to be progressive, guitarist Tor Oddmund Shurke provided his insight on this matter and other subjects in an interview with the monthly music magazine Guitar World. All tracks written by Leprous; all lyrics by Tor Oddmund Suhrke. The album features guest vocals by Ihsahn on the 4th track of the album, "Thorn", and the trumpet on "Thorn" and "Painful Detour" are played by Vegard Sandbukt. Trumpet and additional keyboards were recorded in Kulturkirken Jacob, in Oslo by Rune Børø. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.