Nothing if not a sonic experimenter, the Icelandic chanteuse created a kind of electronica chamber music forefronting harp, strings and choirs, and using empty space itself like Miles Davis might. Björk loves a killer opener and “Hidden Place” (the hidden place is the paradise produced by a loving union) certainly qualifies, awash as it is in the voices of a swirling chorale. Music boxes pervade “Pagan Poetry,” and “It’s Not Up to You” recommends letting go and surrendering to the guiding force of the universe. Vespertine mainly concerns itself with sex, intimacy and the comforting domesticity of home. (Its working title: Domestika.)