The Alchemy Index Vols. I & II

The Alchemy Index Vols. I & II: Fire & Water is the fifth studio album by American rock band Thrice. It consists of the first two volumes of The Alchemy Index, a four-disc concept album about the four elements: Fire, Water, Earth, and Air. The band had issues with Island Records, who tried to change their sound with their fourth studio album Vheissu (2005). By July 2006, they were working on its follow-up, which would become The Alchemy Index project; recording sessions were held between September 2006 and June 2007 at guitarist Teppei Teranishi's house in Orange County, California. The Fire disc revolved around the band's post-hardcore sound that was prevalent on their older releases, while the Water disc focused on the Ambient electronic and trip hop genres.

The Alchemy Index Vols. I & II: Fire & Water received generally favourable reviews from music critics, some praising Thrice's decision to experiment with their sound, while others felt the band followed the themes too directly. It peaked number 24 on the US Billboard 200, as well as charting in Canada and the United Kingdom. Island Records was dismayed by the lack of a radio-friendly song; the band left the label and signed with Vagrant Records. They supported the album with appearances at the Reading and Leeds Festivals in the UK, prior to a US tour alongside Brand New and MewithoutYou; a music video was later released for "Digital Sea".