I don’t think heavy metal has much to do with rock ’n’ roll. Before you get steamed up about how critics are always categorizing everything, I should point out that metal, like prog, is music that invents its own sharply defined category even as it appears to transcend classification. It could be that the German metal heroes Scorpions’ most notable track from their ’70s heyday is 1978’s “The Sails of Charon,” a tune that benefits from Düsseldorf-born guitarist Uli Jon Roth’s neoclassical guitar solo. In fact, the music Roth has made in his post-Scorpions career — he left the band in 1978 — is a superb example of metal’s affinity for the European classical tradition. You may want to check out Roth’s symphonic works, but I appreciate his 2008 prog extravaganza Under a Dark Sky, which sports titles such as “Techno Man” and “Inside the Titanic.” It’s gloriously overblown and pretentious and charming — hey, maybe Roth understands rock after all. EDD HURT

