The Indigo Girls have returned to what they do best — acoustic guitars and soaring harmonies.

After the guest-vocalist-overload and over-production of 1999's Come On Now Social, the girls were ready to revisit what has made them indie icons for the past 15 years.

Their recent release Become You is a simple, lovely album that flourishes with back-to-the-basics Indigo style.

Amy Ray and Emily Saliers are the yin and yang of the Indigo Girls. Ray's smoky country flavor blends smoothly with Saliers' delicate, Joni Mitchell-esque elegance.

Their songwriting and vocal techniques contrast and compliment one another, offering listeners a satisfying fusion of rock and folk, political and personal.

Ray and Saliers write jarring and gentle melodies that disturb and lull their listeners with issues like racism, sexism and love affairs.

The Girls modified their usual independent songwriting methods for Become You, for the first time contributing to one another's tunes.

Become You producer Peter Collins is an Indigo Girls veteran, having produced other Indigo classics including their 1989 self-titled release, which yielded their most popular song yet — "Closer to Fine."

The new album's title track, "Become You," dances with the same reflective, foot tapping exuberance as "Closer to Fine." Ray provides the attitude for the lead vocals and Saliers' harmonies flutter on this catchy track that examines racism in the South.

Though essentially an activism song, many of its lyrics take a personal tone, as is common in the Indigo realm.

Taking an even more personal tone but retaining the same head-bopping brilliance is Become You's opening track and first single "Moment of Forgiveness." A tangy redemption song, "Moment of Forgiveness" layers Ray's resonant vocals over the pulsation of a soulful organ.

Ray shows great range as a songwriter, crafting her melodies with soul, Latin and country influences. But Saliers' trademark ballads are among the album's standouts.

Saliers' gauzy "Deconstruction" is Become You's warmest, most heartfelt track. Thick with angst and regret, "Deconstruction" is a fragile relationship-centric serenade with a graceful, lingering rhythm.

Even more dazzling than "Deconstruction" is cry-along "Hope Alone," in which Saliers shines like a tear trickling down a cheek. "Hope Alone" glistens with all-too-true lyrics like "It's funny what you know and still go on pretending" and "We were just an empty dream too big for hope to fill." Its string arrangements quiver delicately and its intense harmonies glow.

Following "Hope Alone" is Ray's pick-up-truck-and-hound-dog hoedown "Bitterroot," which is one track worth skipping unless you're looking for something more country than a bowl of grits.

However, Saliers' somberly fervent "Our Deliverance" redeems Ray's botched effort. "Our Deliverance" is an essential listen for any pacifist or any individual looking to understand war's sorrow and destruction.

Full of much sorrow but just as much joy, Become You's 12 tracks bloom with acoustic depth and elaborate vocal harmonies. The album may be simple and classic for the Indigo Girls, but it's anything but stale or standard musical fare.