Australia’s Hoodoo Gurus have been one of the most powerful guitar-pop bands of the past few decades. In the ‘80s, their energetic, unpretentious pop music predated the alt-country music scene and shadowed the R.E.M. slide towards enigmatic folk-rock. Albums such as Stoneage Romeos,Mars Needs Guitars! and Magnum C*m Louder were essential college-radio listening that helped keep strong the alternative rock scene before Nirvana came along and blew the doors wide open. Purity of Essence is the sound of the band grown older and wiser but no less serious about keeping the rock and the roll in their attack. “Ashamed of Me,” “Over Nothing” and “The Stars Look Down” may exhibit a more serious philosophical intent, and “Evening Shade” slows things to a mature mid-tempo, but the quick-slashing guitar chords of “You’ve Got Another Thing Coming” and “Crackin’ Up” and the boogie riff of “Only In America” and the buckling rhythm of “Somebody Take Me Home” prove the band haven’t lost their youthful fight.