Ghosts I–IV

Ghosts I–IV is the sixth studio album by the American industrial rock band Nine Inch Nails, released by The Null Corporation on March 2, 2008. It was the band's first independent release following their split from longtime label Interscope Records in 2007. The production team included Nine Inch Nails frontman Trent Reznor, studio collaborators Atticus Ross and Alan Moulder, and contributions from Alessandro Cortini, Adrian Belew, and Brian Viglione.

Reznor described Ghosts as "a soundtrack for daydreams," a sentiment echoed by critics, who compared it to the work of Brian Eno and Robert Fripp. The tracks are unnamed, identified only by their track listing and group number, and are almost entirely instrumental. Although conceived as a five-track EP, the final release consisted of four nine-track EPs, totaling 36 tracks. The album was released under a Creative Commons license (BY-NC-SA) and in a variety of differing packages and prices, including a $300 deluxe edition, without prior announcement. A YouTube-based film festival was also announced, inviting fans to visually interpret the music and post their submissions, but no mention has been made of the festival since its announcement.

Ghosts I–IV received positive reviews; critics praised its experimentalism and unorthodox release. It reached number 14 in the US, and was nominated for Grammy Awards for Best Rock Instrumental Performance and Best Boxed or Special Limited Edition Package, the first time music released under a Creative Commons license had been nominated for a Grammy Award.

Ghosts preceded a series of soundtrack albums recorded by Reznor and Ross, including five collaborations with director David Fincher. In March 2020, Nine Inch Nails released two follow-up albums to Ghosts I–IV: Ghosts V: Together and Ghosts VI: Locusts.