Lost in the Sound of Separation is the sixth album by Underoath. The album was released on August 30, 2008, in some markets, September 2, 2008, in the United States, and as late as September 19, 2008, in Italy. The album title is taken from a line of the lyrics of "We Are the Involuntary". In an interview with MTV News about the effort, the band stated it featured 11 songs that total around 42 minutes. It is the band's last release with founding member and drummer, Aaron Gillespie.