It’d be a couple years before they truly earned their chiseled features, but Mk II studio album number one became as much a keystone for hard rock and metal to come as Black Sabbath’s debut the same year. White-knuckler “Speed King” announces their intentions to get that motor running and side two transforms the blues and psych rock into unstoppable boulders. “Child of Time” is the one for the ages, though, its slow build organ riff leading to an unexpected and unhinged primal howl from Ian Gillan that tears right through the time-space continuum and into your very soul.