As the story goes, when asked to define country music, songwriter Harlan Howard retorted, “Country music isn’t nothing but three chords and the truth,” and many have lived by those words of wisdom ever since. A lot of folk music abides by the same constraints. Heck, a lot of ALL music does. Every now and then, though, a songwriter comes along who defies every constraint the world attempts to place on her.

Hello, Ani DiFranco.

Where DiFranco fits within the songwriting ecosphere is on a level all her own. Although she might, occasionally, let Joni Mitchell, Joanna Newsom, or Jane Siberry visit. DiFranco is one of the most imaginative and adventurous artists of her generation, though she rarely gets recognized as such by the broader music world. Her unique tunings, progressions, arrangements, and phrasings are very often true wonders to behold.

In tandem with her new memoir, No Walls and the Recurring Dream, DiFranco has revisited 16 songs from across her 30-year discography on No Walls Mixtape. It’s fascinating to hear these compositions rendered with hard-earned, middle-aged calm rather than the fearless, youthful rage of decades past. (Good grief. Ani DiFranco is middle-aged!) She has, by her own admission, taken some liberties with lyrics and chords, mostly for age-related reasons — either memory or maturation. But the songs, nevertheless, stand their ground with as much grit and grace as ever. Most of them also tie themselves to moments in the memoir, except “To the Teeth,” which she did just to do it, and with Billy Bragg, to boot.

Two great studies in the contrasts are “The Whole Night” and “Anticipate,” both originally from 1991’s Not So Soft and revisited on 1993’s Like I Said album. Here, DiFranco is joined by Amy Ray and Maceo Parker, respectively. Both songs sound and feel fuller, richer, deeper than ever before. Really, pretty much all the new versions fit that bill. Interestingly, she chose to include three cuts — “Subdivision,” “Grey,” and “Imagine That” — from one of her most mellow releases to date — side b of 2001’s Revelling/Reckoning double LP. So those don’t venture that far from their originals, though “Imagine That” takes on rather more jazzy hues.

Indeed, for fans who hopped on the Ani bandwagon in the past 15 or so years, No Walls Mixtape is a great way to explore early catalog songs whose original renderings might have felt a bit… aggressive. One of the things DiFranco has learned and practiced along the way is that a spoonful of sugar really does help the medicine go down. In her case, simply smoothing out some of the sharp, outer edges allows her to more easily make her sharp, inner points. (To be fair, though, she didn’t include many of her most biting works.)

No Walls Mixtape clearly isn’t meant to be any sort of “Greatest Hits” or even “Best Songs” collection, but a companion soundtrack to the autobiography. And it fulfills that mission exceedingly well.