The latest chapter in the odyssey of Beck Hansen opens with a grandiose declaration: "Put your hands on the wheel, let the Golden Age begin."

It's road-trip time, and Beck, that revered poet of postmodern dislocation, is revving the engine. Desperate to ditch the cares of the world, he's looking for a sliver of frontier that hasn't yet been subdivided, a place far enough away for him to smell possibility in the air.

His words tell of buoyant new beginnings, but there's nothing resembling optimism in Beck's voice. Absolutely no sunshine at all. He's hurt and haggard, resigned and deflated - a man old before his time, puzzling over what once might have been love.

That's right. Love. Say good-bye to battery-acid Beck, master of the arch inside joke. And prepare to welcome Beck the Troubadour, now irony-free, capturing human vulnerabilities in ways he never has before.

The austere, jarringly beautiful Sea Change (Geffen ****) is a masterwork we never expected from the boyish-looking baritone, a triumph of content over conceit that belongs next to The Band's Music From Big Pink and Neil Young's After the Gold Rush on the shelf where pop's highest accomplishments are stored.

It's nothing fancy, really, a series of earnest lost-love songs cradled by acoustic guitar choirs, weepy pedal-steel counterlines and spangled, scene-stealing strings. Set in the key of suffocating gloom, they're not uniformly brilliant. (Some bear traces of Gordon Lightfoot, or the more maundering side of Nick Drake.) But they're made brilliant by Beck's stoic delivery. His characters' wounds are laid bare over dutiful, even indifferent rhythm guitars, their hurt betrayed by a mood of laconic whateverness.

It turns out that Beck is downright devastating when he means what he says. At age 32, he's let go of the lyrical abstractions that, at times, served as a crutch on 1999's Midnite Vultures. He's junked the free-associative wordplay, too, and held in check the inclination to glorify kitsch that drove parts of his 1998 side project, Mutations.

On Sea Change, instead of loading verses with image after tawdry image, he strips them to their essence, capturing the hauntingly familiar feeling of being abandoned ("it's nothing that I haven't seen before, but it still kills me like it did before"), offering straightforward expressions of devotion ("I just wanted to be your good friend"), and describing the feeling of being blown apart from 10 angles.

Beck's lyrical acuity is paralleled by his stark, understated music. None of the 12 songs on Sea Change moves at what could be called a brisk clip. They feel suspended in time, oozing like cough syrup poured from an old bottle, their agonizing slowness intended to underscore the agony of the soul that inspired them. In his new sensitive-guy threads, Beck resists the temptation to dazzle. Suddenly, the joker is a straightman; he sings everything as if it were a concession speech - simply, curtly, leaving poignant splotches of open space between each phrase.

He's not trying to "sell" the songs the way a wheedling John Maher-type songwriter would. By choking back the pain, he makes tales of commonplace heartache genuine, and locates aspects of the wrenching thing called love that, remarkably, haven't yet devolved into cliche.

It helps that Beck has some serious melodies to sing - lush little motifs such as the dreamy "Round the Bend," gorgeously sloped weepers such as "Guess I'm Doing Fine" and the studio-orchestra gem "Lonesome Tears," whose apocalyptic, screen-epic bridge would have made Harry Nilsson envious. The string arrangements, written by his father, David Campbell, convey the sweep of Beck's mission: Sometimes violins and cellos swell up and demand the spotlight, but just as often they scurry around, cushioning the blows dealt by his distraught voice, providing punctuation.

Yet, even when the orchestra is roaring, Beck sounds as if he's calling from the far side of a desolate prairie. Unlike his pop labyrinths and even his gut-level blues evocations, this is music of deep contemplation. But it has none of the manipulation of so many sad songs: Beck strives for a melancholy that takes you somewhere, an ecstatic state that brings pain and awareness in equal measure.

On "Sunday Sun," he gathers ideas from disparate worlds - a theme reminiscent of Jeff Buckley's plaintive cries, slippery vocal improvisations that recall Pakistani qawwali legend Nusrat Fateh Ali Khan, the summer-surf idealism of Dennis Wilson - into a massive complacency-challenging sound that's awesome in its beauty and more ambitious than anything attempted in pop this year.

And though he's borrowing, liberally, from acoustic music of the early '70s - both the British folk of Nick Drake and John Martyn and the California singer-songwriter productions of Neil Young, Joni Mitchell, Jackson Browne, and America - he's improving on those touchstones, incorporating them into grand, harrowing music that brings metaphysical lightness to the travails of relationship.

Sea Change may seem, initially, like nothing you haven't heard before. But listen closely because, in its quiet way, it startles like nothing Beck has done before.