Mixing heavy blues with wild psychedelia, Deep Purple helped invent modern hard rock. Since forming in '68, they've sold millions of albums and influenced countless bands despite a series of dizzying lineup changes. Legendary shredder Ritchie Blackmore and gifted shouter Ian Gillan led the band from '69 through '73, releasing era-defining albums like Machine Head. Later incarnations would feature guitar hero Tommy Bolin and metal heartthrob David Coverdale, but Blackmore and Gillan would finally return in '84. The group continues to record and tour, having lost none of its passion.