After parting ways with Uncle Tupelo partner, Jay Farrar, Jeff Tweedy's first step was a wobbly one-- Wilco's A.M., like a nervous houseguest fidgeting to get comfortable on the couch, never found its vibe. On the other hand, Farrar, with his band Son Volt, confidently assumed his position as Americana's standard bearer. Things changed a bit as 1996's sprawling and ambitious Being There saw Wilco re-imagine themselves as rock n' roll revivalists with a drunken swagger. The band then teamed with Brit folkie Billy Bragg to animate a collection of Woody Guthrie lyrics on 1997's Mermaid Avenue. Wilco lent its Midwestern sensibility to the project, but with Guthrie putting the words in his mouth, Tweedy had yet to beat the biggest knock against him. By now, it was obvious that he had a knack for crafting instantly memorable melodies. But what did he have to say?

Just as the Velvets' swan song was an album Loaded with hits for critics who claimed that Lou Reed couldn't write one, so too is Summer Teeth Jeff Tweedy's statement of purpose. The album, a loose song cycle considering the intermingling of perception, communication and reality, and its affect on our relationships, witnesses the band dismissing its country- rock sound for a studio sheen that would make Brian Wilson proud. Drawing on the pop music of their late '60s and early '70s youths, the band members have crafted a collection of immediately infectious and consistently pleasing melodies with complex, layered arrangements. Having jettisoned Max Johnston along with his dobro, fiddle and mandolin, the songs are driven not by rustic guitar licks, but rather by Jay Bennett's grand organ fills and ever- present harmonies that paint the album in technicolor.

Undermining this sticky- sweet pop party in a delicious irony, and ultimately supplying Summer Teeth with its depth and success, is Tweedy's dark contemplation. The intrigue begins quickly on the album's opener, "Can't Stand It," which finds our narrator lamenting the end of a relationship over a pop-soul ditty punctuated with bells. As the source of the narrator's frustration crystallizes on his own fickle emotions, Tweedy plants the seeds of mistrust, warning of "speakers speaking in code."

As the album racks up false realizations, startling confessions, and outright lies, listeners find themselves exchanging suspicious glances with their guides. While "Pieholden Suite," dupes a sleeping lover, the frail "We're Just Friends" finds our narrator lying only to himself. Similarly, the singer's resolve on the jubilant would-be self- help anthem "Nothing'severgonnastandinmyway(again)" is plastered like a forced smile, and cracks like "I'm a bomb, regardless" scar the façade. In fact, during the album's first half, only the overtly sarcastic "How to Fight Loneliness" is what it seems.

The album's confusion climaxes during its keystone, the majestic "Via Chicago," and its counterpart "ELT." On "Via Chicago," a scorned lover stews: "I dreamed about killing you again last night/ And it felt alright with me." Then, a couplet of unsettling stream- of- consciousness lyrics gives way to Tweedy as he tears into a disturbingly deliberate, off-key guitar riff that might very well be the musical moment of 1999. On the contrary, the celebratory "ELT," finds our sad psychopath repented and healed: "Oh, what have I been missing/ Wishing, wishing that you were dead." Taken on its merits, the song is almost unimaginatively sincere, but in context, it becomes enigmatic. As the narrator shuffles his story for our approval, which spin are we to believe? Summer Teeth's brilliance comes in leaving such questions unanswered.

As Tweedy removes his trickster mask for "My Darling," a spare lullaby to his young son, the mood of the album emerges, but Summer Teeth's transformation is most apparent in its two recitals of "A Shot in the Arm." Amidst the incertitude of the album's twilight opening, its chorus, "Maybe all I need is a shot in the arm/ Something in my veins/ Bloodier than blood," seems a ghoulish reference to drug addiction. However, its reprise, on the heels of the Elvis Costello- by- way- of- Phil Spector romp, "Candyfloss," seems a call on an inner strength and the fortitude to improve.

From its opener, in which "our prayers will never be answered again," to "In a Future Age," where Tweedy challenges us to "turn our prayers to outrageous dares," Summer Teeth drags us through our interpersonal garbage, only to politely ask us to pick up after ourselves. Once drawn in by the album's addictive pop hooks, Tweedy and company ensnare us with clever ironies and rich musical treatments that don't let go. As the album admits its intricacies, it's clear that the band is growing exponentially. Confidently rid of their alt- country ghosts, Wilco is a band from which we can expect everything and nothing at all. With Summer Teeth they deliver on both counts, crafting an album as wonderfully ambiguous and beautifully uncertain as life itself.

-Neil Lieberman