Bjork's upcoming album, "Medulla," finds the artist singing over rhythms fashioned by such beatboxers as former Roots member Rahzel, Shlomo and Dokaka. As previously reported, the 14-track set is due Aug. 31 via Elektra. It was produced by Bjork, with assistance on four tracks by longtime collaborator Mark Bell.

Other guests include Fantomas/Mr. Bungle principal Mike Patton, singer/songwriter Robert Wyatt (on the duet "Submarine"), classical vocalist Gregory Purnhagen, Inuit throat singer Tagaq and the Icelandic and London Choirs. Programming was supplied by Matmos, Mum's Valgeir Sigurdsson, Olivier Alary and Jake Davies.

A limited edition of "Medulla" will sport expanded artwork and a 16-panel poster. According to her spokesperson, Bjork is not expected to embark on a full tour in support of its release. It is unclear if select dates are a possibility.

"Medulla" is the follow-up to 2001's "Vespertine," which debuted at No. 19 on The Billboard 200 and has sold 368,000 copies in the United States, according to Nielsen SoundScan.

Here is the track listing for "Medulla":

"Pleasure Is All Mine"
"Show Me Forgiveness"
"Where Is the Line?"
"Vokuro"
"Oll Birtan"
"Who Is It (Carry My Joy on the Left, Carry My Pain on the Right)"
"Submarine"
"Desired Constellation"
"Oceania"
"Sonnets/Unrealities XI"
"Piano II"
"Mouths Cradle"
"Wednesday (Midvikudags)"
"Triumph of a Heart"