Nine Inch Nails are a pretty amazing phenomenon when one considers what they--um, he--have done with just a few studio recordings. The Downward Spiral, NIN's second full-length album, is just as packed with vitriol as Pretty Hate Machine and the EP Broken--and has just as solid a base of pop hooks that go a long way toward explaining NIN's popularity. Most recognizable is the down-tempo single "Closer," which remains a staple of dance clubs everywhere. But for the most part, the album is all heavy beats and aggressive guitars--industrial music with a pop angle. That winning combination is what makes Trent Reznor a law unto himself, becoming insanely popular while the main body of industrial music retains its subculture status. --Genevieve Williams