Tom Morello's adventurous musical spirit stems from both his formative influences—he worshipped hard-rock trailblazers Kiss and Black Sabbath—and his deep commitment to sonic ingenuity. As a member of '90s rap-rockers Rage Against the Machine, the guitarist unleashed thundering, bombs-away riffs indebted to hip-hop and punk. Beyond Rage, Morello has branched out into smouldering metallic nihilism (A$AP Rocky's "FTW") and supersonic funk grooves (Prophets of Rage's "Living on the 110"). And on a sombre update of Bruce Springsteen's "The Ghost of Tom Joad", he conveys gravitas with world-weary vocals and anguished guitar scribbles.