Rush became full-blown prog-rock gods in 1976 with their fourth album, 2112—best remembered for its behemoth first side, a dystopian sci-fi concept suite about one man’s discovery of an ancient, outlawed electric guitar. Four decades later, that 20-minute piece represents the genre at its dorkiest, with bassist Geddy Lee shrieking about the “priests of the Temples of Syrinx” in a glass-smashing range similar to a dog whistle’s. This 40th anniversary edition, newly remastered at Abbey Road Studios, is the essential version—if only for its creative twist on the reissue format. The second disc includes a handful of eclectic cover versions by famous Rush fans, like power trio Dave Grohl, Taylor Hawkins and Nick Raskulinecz, adding tricky rhythmic shifts to the grand “Overture,” and Alice in Chains amplifying the mellotron-laced melancholy on acoustic ballad “Tears.” Best of all is Steven Wilson’s reimagined take on “The Twilight Zone,” full of jazzy Wurlitzer piano and stacked vocal harmonies. Meanwhile, the original 2112 remains a fascinating, flawed classic. And now’s the perfect moment to reevaluate the album’s underrated second side: “The Twilight Zone” and “Tears” both showcase Lee’s powerful lower vocal register, and with bass beast “A Passage to Bangkok,” the Canadian trio made tour bus weed-smoking sound like mythical subject matter. Rush perfected the concept LP in 1978 with the eerier, less on-the-nose Hemispheres. But for many prog diehards, 2112 is still their shining moment among the vast galactic stars.