Austin, 2012: A Lululemon yogawear store has popped up at Sixth and Lamar, near the original Whole Foods, and at least one person aims to fight this capitalist incursion. Meet Roxy, the underemployed, oversexed and hopelessly earnest heroine of Mary Pauline Lowry’s new novel “ The Roxy Letters .”

At a time when epistolary novels seem almost quaint, Roxy’s letters reinvigorate the form. Urgent and witty, they are addressed to her hapless one-time beau and current roommate, Everett. No matter how many ground rules Roxy, a part-time “deli maid” at Whole Foods, establishes in these missives, Everett finds new ways to frustrate her, pilfering her vegan foodstuffs, encouraging the consumption of brie and bringing home fliers for “Nest Life,” an “orgasmic meditation” group.

Ah, keep Austin weird! Although Roxy knows that her beloved city has not been properly weird since the 1990s, she’s still devoted to the Spider House for coffee, Torchy’s for tacos and Kerbey Lane Café, despite the temptation of their delicious queso. Anyone who has ever spent more than a layover in the Texas capital will understand that, while there are several manic subplots involving Roxy’s love life and political convictions, “The Roxy Letters” functions best as a paean to Austin, that urban paradox of a blue city plopped down in the heart of a red state, a place that could nurture Whole Foods into a national chain, then lose it to a conglomerate.

Roxy’s righteous rage against the corporate sanitization of her favorite corner of the universe leads her to community organization. With beloved but elusive new best friend Artemis Starla, she plots a protest to drive Lululemon back to suburban shopping malls. “That store’s arrival is a symbol of the sort of change that will price us all out of this town,” writes Roxy, who also notes that she had the foresight to use an inheritance from her grandmother as a down payment on her little house.

Austin contains a glorious concatenation of tensions, and Lowry employs her heroine as both a catalyst for many of them and an archetypal resident. Whether she is rising in the ranks at Whole Foods due to her real artistic talent, or embarking on a new relationship, or taking in live music at the Deep Eddy Cabaret, Roxy embodies the can-do, New-Age, try-anything-once spirit of her burg. With a tendency to exclaim “Oh Goddess!” and to complain about her cheese-induced acne beard, Roxy is good for a laugh, but her sincerity is even more affecting, especially when it comes to loving a place that has made insiders of so many outsiders.

Reading “The Roxy Letters” is as refreshing as a dip in Austin’s beloved Barton Springs natural swimming hole, the kind of comic novel we need right now. Not just because it is fun, funny and filled with eccentrics, but because Lowry’s novel proves that good people working together can make positive changes. Sixth and Lamar may eventually fall to corporate greed, but the transformations in Roxy and her circle of friends? Those are permanent.

Bethanne Patrick  is the editor, most recently, of “The Books That Changed My Life: Reflections by 100 Authors, Actors, Musicians and Other Remarkable People.”

The Roxy Letters

By Mary Pauline Lowry

Simon & Schuster. 309 pp. $26