Virtuoso blues records by white British dudes often leave a bad taste. Former Procol Harum guitarist Robin Trower may have been a whiter shade of pale but his 1974 breakthrough is the exception that proves the rule. Post-Cream, post-Hendrix, post-Zeppelin, he brings all those influences to these off-kilter heavy psych jams and infuses them with an energy often lacking in sixties Brit blues interpreters (usually acts with “blues” in their name). The secret? While Trower’s guitar acrobatics are the big selling point, his rhythm section (James Dewar and Reg Isidore) keeps slipping out from under him and give everything a seriously funky feel. Songs like the title track and “Day of the Eagle” have been covered by metal bands ranging from Armored Saint to Opeth. It’s not just because of the technical difficulty — the underlying emotional impact provides the support structure for this bridge.