The duet isn't the most prevalent of pop forms in 2017. While legends such as Barbra Streisand, Tony Bennett, and John Prine may still favor it, the traditional vocal collaboration has become more of a one-off among contemporary artists. Long gone are the days when stars in their prime – see Lee Hazelwood and Nancy Sinatra, or Serge Gainsbourg and Jane Birkin – used the duet to explore differing vocal dynamics. However rare, the duet isn't exactly extinct. This week brings us Not Dark Yet, a striking new album from roots/county veterans Shelby Lynne and Allison Moorer. In honor of their collection of songs that taps a familial bond, we reflect on five of our favorite modern-era duet records.

Mark Lanegan and Isobel Campbell, Ballad of the Broken Seas
He's a husky, gruff-voiced baritone. Her vocals feel suited for an angelic lullaby. Such pairing of opposites – a contrast in tones, themes, and approaches – seems as old as fables. Imagine an updated version of Hazelwood and Sinatra, only Ballad of the Broken Seas unfolds as a complete mystery. The songs plant roots in Americana (see the cover of Hank Williams' "Ramblin' Man"), yet remain obscured to conceal any sense of time or place. Guitars sound sharp and hollow, capturing a Western spirit, while sea-chantey atmospheres add to a low-key restlessness. Campbell serves as a force of light, but Lanegan's shadow of darkness proves inescapable.

Robert Plant and Alison Krauss, Raising Sand
Another unlikely pairing – and one that proved beneficial to both parties in terms of chart success and Grammy accolades. Rather than chase nostalgia-fueled dollars by touring with Led Zeppelin, Plant continues to dig deep into America's past, exploring folk, blues, and country strains that helped lay the foundation for rock n' roll. Krauss, meanwhile, reigns as country-pop royalty. Her work possesses a mix of reverence and beauty for roots music. On Raising Sand, Plant's primal vocals work against Krauss' earthy tones to create haunting settings. Reverberating guitars further the swampy atmospherics. And songs such as "Please Read the Letter" and "Stick with Me Baby" emit a beguiling low-key romanticism, with echoing rhythms falling somewhere between lonely and comforting.

Sam Beam and Jesca Hoop, Love Letter for Fire
In a youth-obsessed medium preoccupied with drama, this collaboration between folksy orchestrator Sam Beam and solo experimentalist Jesca Hoop emerges as the rare album to zero-in on the ups and downs of mature relationships. The songs don't feel so much like duets as intimate conversations between two familiar people. Beam and Hoop dance around concepts with metaphors only a shared brain would understand. Sometimes they shadow one another. But often, they answer each other to present two sides to a story. The music is contemplative and graced with a choir-like glow – a warming sound designed to temper flare-ups. While arrangements may be punctuated with brief percussive oddities, Love Letter for Fire remains typified by songs such as "We Two Are a Moon," where companionship fuels a heartbeat.

The Both, The Both
When it comes to the duet, we tend to think of romantic songs or works that play up artists' dissimilarities. Yet Ted Leo and Aimee Mann throw caution to the wind as the Both, concocting fare on a 2014 self-titled album that emphasizes breezy pop melodies and exuberant harmonies. Sonically, this is a work wherein spirited guitars lead Leo and Mann in and out of conversation with one another. Even when the pair slows down the pace, as on "Hummingbird," the songs unfold like rock n' roll fairy tales. Dig beneath the surface, and it's clear these nuggets demand further exploration.

Shelby Lynne and Allison Moorer, Not Dark Yet
Sisters Lynne and Moorer had never collaborated on an album despite a recording career that counts more than 20 solo works between them. They rectify the oversight on Not Yet Dark, which comes out this week and takes its name from a Bob Dylan song. Here, they aim to upend country traditions and do so by tackling songs from the likes of Nirvana, the Killers, Nick Cave, and the Louvin Brothers. All the while, they loosely focus on material that touches on spirituality or the deep bond between two people. Forgiveness courses through "Every Time You Leave," and the title track emphasizes perseverance. What stands out most is the way their voices become one – a celebration of the healing power of song.

Photo credit: Jacob Blickenstaff