"Bye Bye" is a song by American singer and songwriter Mariah Carey, taken from her eleventh studio album, E=MC² (2008). She co-wrote the song with its producers Mikkel S. Eriksen, Tor Erik Hermansen and Johntá Austin. It was released as the album's second single on April 15, 2008. The song is influenced by pop and R&B music genres, and features a piano and keyboard-driven melody. Lyrically, the song is a dialogue in between Carey and her deceased father throughout the verses, and a universal salute to departed loved ones on the chorus.