I Am... Sasha Fierce is the third studio album by American singer Beyoncé. It was released on November 15, 2008, by Music World Entertainment and Columbia Records. In its initial release, the album was formatted as a dual disc, intending to market Beyoncé's contrasting facets of artistry. The first disc, I Am..., contains slow and midtempo pop and R&B ballads, while the second, Sasha Fierce (named after Beyoncé's on-stage alter ego), focuses on more uptempo beats that blend electropop and Europop genres. In composing the songs' lyrics, Beyoncé worked with many writers, with each session accompanied by live orchestration.