It's anybody's guess why Little Big Town's three fine singles from 2007's excellent A Place to Land failed to crack the Top 30, or why the album didn't build upon the platinum success of its predecessor, The Road to Here.

That said, the bluesy roil in "Little White Church," the pre-release single from The Reason Why, LBT's fourth studio album, proves that failure was a fluke.

The trademark four-part harmony that separate them from the rest of the contemporary country pack isn't the only thing: their group songwriting -- with producer and guitarist Wayne Kirkpatrick as a fifth member -- is classy, sophisticated, and doesn't rely on genre clichés.

While the '70s-period Fleetwood Mac and the Eagles were clear inspirations and influences earlier, here they've been integrated into a sound that is LBT's own.

The guitars are a little fiercer, the harmonies looser, and therefore more emotionally expressive; they reflect the growth in their lyrics.

And even as Karen Fairchild is asserting herself as a de facto frontwoman, the contributions made by Kimberly Schlapman, Jimi Westbrook, Phillip Sweet and Kirkpatrick create an inseparable whole.

The group wrote or co-wrote nine of the set's 12 songs, including the single, and it's their songs that shine brightest, beginning with the title-track opener.

With a melody that resembles a 1960s pop song, Fairchild sings solo to a single-string electric guitar riff playing changes; the acoustic guitars fold underneath her voice and then the harmonies kick in to take the entire thing to the stratosphere.

The intro harmonies on "Why, Oh Why" echo both the Louvin Brothers and Gram Parsons and Emmylou Harris, before a nasty electric-guitar vamp, a punched-up kick drum, snare and distorted slide guitar turn this into prime, funky country-rock.

"All the Way Down," introduced by a scratchy vinyl record and harmonies singing the refrain as if from the distant past backed only by a banjo, promptly shifts gears into a prime modern-country song with soaring vocals, mandolins, and an infectious hook.

"Lean into It" is the stripped-down ballad that closes the album.

Gentle guitars and a lonely pedal adorn Sweet's vocal, which is girded by the voices of his bandmates to provide solace during the dark hours we all endure.

The Reason Why is mature, exquisitely crafted, and radio friendly; it ups the ante for contemporary country in songwriting, performance, and production (the latter by stripping away excess).

It's as near to a perfectly balanced recording as one will find in the genre.