Vespertine is the fourth studio album by Icelandic recording artist Björk. It was released on 27 August 2001 in the United Kingdom by One Little Indian Records and in the United States by Elektra Entertainment. Björk aspired to create an album with minimal and intricate electronic music to evoke an intimate and domestic feeling, in contrast with the louder styles of her previous studio album Homogenic (1997). She enlisted producers such as Opiate, Console and the duo Matmos, and has also worked with harpist Zeena Parkins. Production on the album began whilst filming her role in Dancer in the Dark.

Björk composed arrangements with thin-sounding instruments, including the harp, the celesta, clavichord, strings and custom music boxes. Assisted by Matmos, Björk created "microbeats" from various commonplace sounds, such as that of shuffling cards and ice being cracked. Lyrically, the album revolves around Björk's new relationship with Matthew Barney, featuring themes of sex and love. Other lyrical sources include the poetry of E. E. Cummings and British playwright Sarah Kane's Crave. Three singles were released from Vespertine: "Hidden Place", "Pagan Poetry", and "Cocoon". The music videos of the latter two were banned on MTV for their depictions of sexuality. Björk embarked on the Vespertine world tour with Parkins, Matmos, and a choir of Inuit women, where they performed at theatres and small venues in favor of acoustics.

The album peaked at number 19 on the US Billboard 200 selling 75,000 copies in its first week and at number 8 on the UK Albums Chart. It was certified gold in Canada, France, and the United Kingdom. Noted for its erotic, intimate mood and sonic experimentation, Vespertine received universal acclaim from music critics, with some considering it Björk's best album to date. The album appeared on several publications' lists of the best albums of 2001 and of the decade, and has been evaluated by many critics to be one of the best albums of all time.