There's a wonderful, plaintive voice singing Kitty Wells' "The White Circle on My Finger," that eerily opens Terri Clark's Classic.

That segues into Clark and band ripping into a barroom-stomping read of Wells' "It Wasn't God Who Made Honky Tonk Angels." That uncredited voice at the beginning belongs to Clark's grandmother, who sang country songs to her as a child.

Classic is Clark's tribute to country music's illustrious heritage.

Documented here are some of the songs and artists who inspired her to follow a path that has had its share of highs and lows commercially and personally, but which has always been satisfying aesthetically.

Co-produced with Jeff Jones, Clark's selection of timeless tunes holds plenty of surprises.

In two instances, she duets with the recording artist who scored with the song in the first place: "Delta Dawn" (the first song Clark learned to play and sing) features Tanya Tucker, and "How Blue" pairs her with songwriter Reba McEntire.

Other duets include "Golden Ring," the George Jones and Tammy Wynette hit, with Dierks Bentley, while the rocking take on "I'm Movin' On" -- written and performed by fellow Canadian Hank Snow -- stars Dean Brody.

Her soulful take on Canadian songwriter Neil Young's "Love as a Rose" is an unlikely but canny choice; while Clark acknowledges the iconic nature of the original in her version, the grain in her voice also plainly reveals an open but fearful heart in her articulation of the song's warning.

Her stinging roadhouse version of Delbert McClinton's "Two More Bottles of Wine" -- made immortal by Emmylou Harris -- bears traces of both songwriter and singer in her reading.

The busted heart and restless country soul in Merle Haggard's "Swinging Doors" is made plain -- and is perhaps more nakedly devastated -- in Clark's expressive voice.

She captures the songwriter's intent with all the vulnerability and resignation his lyric implies.

The sheer tenderness and longing in her version of John Hartford's "Gentle on My Mind" is closer to the original than Glen Campbell's smash hit, yet she makes it her own.

Clark claims that this is the album she's wanted to record her entire career.

Given the integrity, richness, and passion she puts into these performances, that's easy to believe.

Another title for this wonderful effort might have been "Classy" for all that she invests here, but Clark is too self-effacing for that.

Classic is an essential entry in this singer and songwriter's catalog.