As the biggest thing to ever come out of my hometown of Guelph, Ontario, the Constantines' maturation into Canada's apocalyptic poet laureates of hard work and commitment has been particularly gratifying. Their early albums were too glibly tagged as Springsteen-meets-Fugazi, but with 2005's Tournament of Hearts, the music turned into something weightier, brawnier, and more satisfying as frontman Bry Webb hit his stride, growling about growing up and working full-time. Kensington Heights, like its predecessor, isn't as fiery as the best moments on the band's inconsistent breakthrough, 2003's Shine a Light, but the Constantines still deliver bedrock strength and eternal-flame passion. When Webb bellows, "I just want to see it in a natural light" during "Million Star Hotel," it's transfigured by the band's howling hum into an apotheosis of longing, while pummeling, sweaty tracks like "Hard Feelings" and "Credit River" only confirm that these guys are our finest modern exponents of full-bore, heart-on-sleeve rock 'n' roll.

Guitarist Steve Lambke's "Shower of Stones" (as in: "Oh, love can be a . . .") might be the most direct summation of the way the Constantines wrestle with the bittersweet pangs of really living, but Kensington Heights keeps up the intensity throughout, even on hushed acoustic laments like "New King," until it surges to a halt with "Do What You Can Do," their very own "Don't Be Denied." Like that forgotten Neil Young gem (if Young's reasons for blocking the CD issue of Time Fades Away weren't so personal, I'd be starting a petition), "Do" couches a rousing call to arms in the language of defeat, which only strengthens the point; Webb sounds anguished as he urges you to make do with what you have, which perversely only makes the song more inspiring.

That track also highlights the most surprising strength of Kensington Heights: the way the best songs are neither rockers nor ballads, but partake of the strengths of both forms. Songs like "Time Can Be Overcome" or "Trans Canada" possess the kind of muscularity that makes the Constantines' more punk-inflected songs so exciting, but also the tenderness that shades their more ostensibly gentle moments. It's what makes them one of the few Next Big Things with staying power, and the way Kensington walks that delicate line with aplomb makes it the band's best yet.

The Constantines play the Mercury Lounge April 16, and Southpaw April 19