My colleague's anticipation brought home how underexposed Lincoln was nationally before finding a steadfast champion (as well as a sympathetic producer) in Verve's Jean-Philippe Allard, beginning with 1990's The World Is Falling Down. She opened her set in Chicago that night with the Depression-era anthem "Brother, Can You Spare a Dime?", acknowledging her lineage from Billie Holiday by lagging behind her rhythm section and attacking each note separately in a way that let each word beat like a drum. "That does it," my colleague whispered as Lincoln followed it with "Ten Cents a Dance." "I'm in love."

I tell the story because I've got a hunch that Abbey Sings Abbey, her tenth album with Allard and the first to feature her compositions exclusively (including the droll lyrics to Thelonious Monk's "Blue Monk" that she debuted on Straight Ahead), is going to win Lincoln plenty of new hearts, to whom I say what I said to my buddy in Chicago: Welcome to the club. Focusing on arranger Gil Goldstein's accordion, Dave Eggar's cello, and Larry Campbell's mandolin and pedal-steel guitar in lieu of rhythm-and-horns, Lincoln's accompaniment eclecticizes what are clearly jazz melodies, performed by a jazz singer, into gospel ("The World Is Falling Down"), prairie ballad ("And It's Supposed to Be Love"), chanson ("Love Has Gone Away"), gypsy ("Throw It Away"), cante jondo ("Down Here Below"), and even something close to nursery rhyme ("The Music Is the Magic"). In other words, Abbey Sings Abbey ventures into Norah Jones and Cassandra Wilson territory, but with a depth and complexity that sidesteps Starbucks and World Café cliché along with hidebound jazz conventions.

All I usually ask of jazz producers is that they do no harm. But Allard does right by his artist on this program of self-covers, which seems primarily concerned with drawing attention to how many stirring lyrics Lincoln's written without much fanfare over the decades. (As for her melodies, she worries a dolorous handful over and over—but they get you every time. And their uneven bar lengths and metrical irregularities indicate the words come first and continue to take precedence once the melody is in place.) The softer instrumentation suits a 76-year-old woman no longer equipped to shout the way she did on We Insist. Pitch has never been Lincoln's strong point, but the absence of piano renders that question moot. And players coming from pop, like former Dylan sideman Campbell, tend to be more attentive to the needs of singers than most jazz improvisers just waiting their turn to solo.

As a twilight retrospective, Abbey Sings Abbey might seem to belong to the same genre as Chet Baker's Let's Get Lost and Sinatra's Duets. But whereas those wasted icons of male cool had nothing left by then save their phrasing, Lincoln—who underwent bypass surgery and aortic valve replacement in March, just months after these sessions—is in remarkably good voice. Phrasing is part of it: The way she elides the phrase "now and then" into a rising and softly released sigh toward the end of "Being Me" is an object lesson in what good jazz singing is all about. (Hint: It's not about scatting, which is just another form of filigree.) But the true test is "Down Here Below," essentially a love song to God with a spiraling melody requiring her to begin each new verse with a leap—although her voice is frayed, she's singing full-out and pulling it off.

Given Abbey Sings Abbey's spiritual reach, a better comparison might be to Johnny Cash's stripped-down sessions for Rick Rubin, although Lincoln is interpreting her own material. Maybe because her best lyrics approach poetry (take "And It's Supposed to Be Love," a powerful account of spousal abuse from the point of view of a woman on the receiving end), what I find myself thinking about as I listen isn't another album at all, but Yeats's "When You Are Old," for his warrior woman Maud Gonne—only here it's the pilgrim soul herself measuring her moments of glad grace against sorrows that have always been more evident in her voice than in her changing face.

Most biographical portraits of Lincoln imply that her sporadic discography during what should have been her prime was industry payback for the political edge of We Insist and Straight Ahead. But if she was such a pariah, why did Hollywood cast her opposite Sidney Poitier in For Love of Ivy in 1968, and why was she nominated for a Golden Globe? And wasn't black indignation all the rage in the early '70s, prime time for Nina Simone and Gil Scott-Heron? Blues unrelated to politics may have been what held Lincoln back, but that's a door left closed in interviews. Where she's left it ajar is in her music—in her lyrics, but also in an unconcealed vulnerability at odds with both her militant history and the matriarchal image she's acquired with age. As with Miles Davis on ballads, this vulnerability can be her greatest strength as a performer, and never more so than on Abbey Sings Abbey, where the novel instrumentation (novel for her, anyway) throws it into bold relief. I can't imagine anyone hearing a track from it and not being moved to the quick. She's become our greatest living jazz singer, and this is her crowning achievement.

In showing that Lincoln has written more good songs than the dozen on Abbey Sings Abbey, Kendra Shank's tribute A Spirit Free inadvertently proves that Lincoln's only true interpreter is Lincoln herself. Because her approach is so personal and straightforward—so close to her speaking voice—imitation is out of the question. This forces anyone who would cover her to take a novel approach, which is the only possible justification for the quasi-Navajo chanting with which Shank (sounding more like Sheila Jordan's disciple than Lincoln's) begins both "The Music Is the Magic" and "Throw It Away." The latter's lyrics were inspired by Hexagram 25 of the I Ching, and Shank might think she's restoring them to their mystical origins. But whereas delivered by Lincoln, the lines "'Cause you can never lose a thing/If it belongs to you" come off as hard-boiled as Clive Owen's "Hold on tightly, let go lightly" in Croupier, Shank just sounds sappy. She has a big, plum voice not unlike Linda Ronstadt's, and she swings—she's in her element on a song like "I've Got Thunder (and It Rings)," where momentum is all. But there's a world of difference in hearing the valediction "Hold the curtain open, it's time to take a bow"—from "Being Me," which closes both albums—delivered by a woman in her seventies and by one still in her forties. It's a sentiment too big for Shank, in a way that has nothing to do with the size of her voice.