In the '90s, Nine Inch Nails emerged as the most popular industrial group of the time, penetrating the mainstream with 1994's The Downward Spiral and 1999's The Fragile, bringing the genre to a mass audience and inspiring a crop of imitators. Behind the moniker and famous NIN logo was singer, producer, and multi-instrumentalist Trent Reznor, who, for almost three decades, was the band's only official long-standing member. As the core figure, Reznor remained solely responsible for NIN's musical direction, even when he was supported in concert by a rotating cast of backing music...