The initial set of roadwork from NIN covers 24 cities through early September. The complete schedule is included below.

The group's new studio album, the four-disc all-instrumental "Ghosts I-IV," arrived in unorthodox fashion several weeks ago. NIN leader Trent Reznor composed and recorded the set over a 10-week period last fall, along with help from producers Atticus Ross and Alan Moulder (Depeche Mode), with whom he has worked in the past. Touring NIN keyboardist Alessandro Cortini, veteran musician Adrian Belew, and Dresden Dolls drummer Brian Viglione also contributed, according to the album's website

"This music arrived unexpectedly as the result of an experiment," Reznor wrote in a message posted at the site, which he launched in early March after weeks of teasing fans with brief messages that hinted at a forthcoming project of some sort. "The rules were as follows: 10 weeks, no clear agenda, no overthinking, everything driven by impulse. Whatever happens during that time gets released as ... something.

The first nine tracks from the album--which Reznor released independently, bypassing any major record label--can be downloaded from the band's website for free; all 36 tracks can be purchased for $5. NIN also is offering "Ghosts" in a variety of deluxe packages ranging from $10 to the $300 "ultra-deluxe limited edition," which sold out almost immediately, according to the band.

Earlier this month, NIN's management announced that the project had racked up $1.6 million in direct sales in under two weeks.