Answer by taking a quote from the following article:

Corey Todd Taylor (born December 8, 1973) is an American musician, singer, songwriter, actor, and author, best known as the lead singer and lyricist of the bands Slipknot and Stone Sour. Taylor formed Stone Sour in 1992, playing in the Des Moines area, and working on a demo. He joined Slipknot in 1997 to replace their original vocalist and has subsequently released five studio albums with them. After the first two Slipknot albums went Platinum, Taylor revived Stone Sour to record an album and tour in 2002.

In Des Moines, Iowa, Joey Jordison, Shawn Crahan, and Mick Thomson approached him asking him to join Slipknot. He agreed to go to one of their practices, and ended up singing in front of them. Of Slipknot's nine members, Corey was the sixth to join the band. Performing with Slipknot, he would also come to be known as "Number Eight", being that the band follows a numbering scheme for its members, ranging from 0-8. According to Shawn Crahan, Corey wanted number eight, because it symbolizes infinity.  Feeling he could expand more inside Slipknot than in Stone Sour, Taylor temporarily quit Stone Sour, even though they were recording an album with Sean McMahon. Taylor's first gig with Slipknot was on August 22, 1997, which according to band members did not go well. During his first gig, Taylor did not perform wearing a mask; however, for his second show nearly a month later, Corey wore a mask that resembles his debut album mask. Taylor's current mask was described by MTV's Chris Harris as looking "as though it were made of dried, human flesh--like Leatherface, if only he used moisturizer."  Taylor has recorded with Slipknot since the release of their second demo album, a self-titled demo used to promote the band to prospective labels and producers. As permanent vocalist, he recorded with Slipknot at Indigo Ranch in Malibu, California and released Slipknot, the band's debut album that peaked number one on the Top Heatseekers chart, went double platinum in the United States, and was included in the 2006 book 1001 Albums You Must Hear Before You Die. Taylor was accused of copyright infringement, regarding the lyrics of the song "Purity", but no action was taken. Taylor began recording for their second studio album, Iowa, in 2001 at Sound City and Sound Image in Van Nuys, Los Angeles. It was released August 28, 2001 and peaked number one on the UK Albums Chart, as well as number three on the Billboard 200. While writing Vol. 3: (The Subliminal Verses), Taylor decided to write lyrics that would not warrant an explicit label. It peaked number two on the Billboard 200. All Hope Is Gone was the first Slipknot album to peak number one on the Billboard 200.

When was this released?
2006