MF Doom is the man in the iron mask. The most mysterious figure in hip-hop has also become one of the most popular, supplying beats and rhymes for Gorillaz, de la Soul, Madlib, Danger Mouse, and Wu-Tang Clan, and drawing praise from heavyweights like Just Blaze, Nas, and Mos Def. Since 2002, DOOM has released numerous volumes of Special Herbs, one of the longest-running instrumental series in hip-hop history.