To write about folk music is to confront an assortment of American mythologies, some innocent, some odious. No one really knows what the phrase “folk music” means anymore—songs played on acoustic instruments, with acknowledgements paid (in one form or another) to the past, feels vague enough to be accurate. But even this definition is routinely gnarled to further various agendas, both commercial and ideological. Consequently, it’s hard for a critic to avoid deploying an embarrassing number of scare quotes while trying to sort it all out. For example: “folk” is a genre people associate with rural backwaters and unswept porches, whereas “Brooklyn” is a place people associate with the rebranding and co-opting of “authentic” forms of culture developed elsewhere and now served in Mason jars. To combine these two fantasies, as the Brooklyn Folk Festival has done since 2008, is to lock eyes with a righteous monster wearing a delicate flower crown.

Yet in recent years, the Brooklyn Folk Festival (which is presented by the Jalopy Theatre and School of Music, and will take place on April 28th, 29th, and 30th, at St. Ann’s Church, in Brooklyn Heights) has emerged as one of the most vital and spiritually sound folk-music events in the country. This is due, in part, to its thirty-five-year-old organizer, the Brooklyn-based musician and producer Eli Smith, who curates its offerings with an eye toward the diverse, the spontaneous, the countercultural, and the trenchant. In some ways, Smith is trying to correct for the bastardization of the term itself. “Since the nineteen-fifties, ‘folk’ music has existed as a sub-category within the broader field of commercial popular music,” he wrote to me recently. “In general, this category has, ironically, featured a mix of pretty corny, sanitized, overly earnest and fake-sounding stuff. Blues, string bands, and other old and rural forms of American and world music offer a stark contrast to this ‘folk’ category.”

New York City was the epicenter of a folk-music revival, spanning from the nineteen-forties through the nineteen-sixties, in which music and progressive politics were emphatically entwined. Smith’s bookings—which, historically, have included civil-rights leaders like Mattie Jones, who spoke last year—reflect and further the affiliation. Anyone who has felt aggrieved by the defanging of the music festival (these days, the lineups of most major summer events are interchangeable late-capitalist entreaties, their stages and Porta-Potties so branded as to be disorienting) will appreciate Smith’s devotion to the radical convictions of the genre’s forebears. A folk-music festival, he seems to believe, should require a person to expand his or her thinking.

The festival will open with a reading from the poet and activist Anne Waldman, who, along with Allen Ginsberg and Diane di Prima, founded the Jack Kerouac School of Disembodied Poetics, at Naropa University, in 1974. Waldman has published forty-odd books in her career, and in 1975 and 1976 she was the poet-in-residence with the Rolling Thunder Revue, Bob Dylan’s famed concert tour. She is now seventy-two but no less forceful a performer. The opening lines of her poem “Battery,” from 1996, seem to contain their own definition of folk:

A trio of instruments you love the notes

indissectible & extending small rockets of delight

force to love, be loved, love accelerating

love momentum, the love to travel

we will never agree the world contains

so much phenomena we’ll put on glasses

abstract it give it structure make a frame

inversely proportional to the square of

two distances apart

The Last Poets—a loose collective of writers, musicians, and activists, formed in East Harlem in 1968 and affiliated with the Black Nationalist movement—will perform a headlining set on Sunday night. Earlier this month, they appeared on “B-Side,” a music program on BRIC TV, Brooklyn’s nonprofit cable channel. Although its members are now in their late sixties and early seventies, they appear indefatigable; rancor toward injustice does not seem to mellow with time. The group is routinely credited as one of the earliest progenitors of hip-hop (Gil Scott-Heron, another crucial influence, began recording around the same time), and listening to the Poets’ first records, it’s difficult to deny the ingenuity of their work, or the impact it surely had on generations of young m.c.s, who would have internalized not just the Poets’ particular, rhythmic proto-rap but also their trembling outrage at a system devised to disempower them.

On occasion, though, the group’s fury has been recast as something else entirely. The phrase “party and bullshit,” which is repeated on the Poets’ “When the Revolution Comes,” from 1970, was later borrowed by Biggie Smalls, who, in 1993, used it as a title of a song of his own. In 2004, Abiodun Oyewole, who wrote and delivered the original line, told a reporter from the Detroit Metro Times that he had intended the words as a kind of admonishment. “When we rapped, it was all about raising consciousness and using language to challenge people,” Oyewole said. “When I wrote ‘party and bullshit’ it was to make people get off their ass.” In Biggie’s version, it’s presented as necessary recreation: “Dumbing out, just me and my crew, ’cause all we wanna do is party and bullshit.” Yet this, too, feels somehow in keeping with the folk spirit—the reappropriation of a pejorative, the making new of an old idea.

The weekend will also feature sets by Jerron (Blindboy) Paxton; Jim Kweskin; Thunderbird American Indian Dancers; Ukrainian Village Voices; Peter Stampfel (of the Holy Modal Rounders) and the Ether Frolic Mob; Reverend Billy and the Stop Shopping Choir; a fiftieth-anniversary celebration of Woody Guthrie, Alan Lomax, and Pete Seeger’s “Hard Hitting Songs for Hard Hit People”; a screening of “Shake ’Em On Down,” a documentary about the sharecropper turned bluesman Fred MacDowell; a harmonica-playing contest; a banjo toss (in previous years, it has been heaved into the Gowanus Canal, lugged out via rope, and then heaved again, until the farthest heave has been determined and a winner honored); a square dance; various singing and instrument-building workshops; a puppet show; jam sessions; and more. The unifying theme is, as ever, resistance—against a narrowing world view, against marginalization, against homogeneity, against consumerism.

The festival’s mission feels especially timely this year. There’s been outrage, recently, at the corporatization of protest: the model and reality-television star Kendall Jenner starred in a widely reviled advertisement for Pepsi, released earlier this month, in which she joined what appeared to be a Black Lives Matter march and then gamely offered a can of soda to a police officer. “We did not intend to make light of any serious issue. We are pulling the content and halting any further rollout,” Pepsi quickly offered, after what felt like instantaneous and unilateral criticism. It’s always curious to see exactly what a culture’s tipping point is—how it will protect what it decides is pure, and, moreover, how it will ultimately define advertising. (Pop stars such as Beyoncé have successfully featured imagery associated with Black Lives Matter in music videos, inadvertently suggesting more and perhaps bigger questions about art, commerce, and the re-contextualization of folk movements.) Unfortunately for Pepsi, the notion that police brutality could be neutralized or rectified by the gifting of a soft drink was too much for anyone to bear.

Folk music has been plagued by prissy skirmishes regarding truth and sanctity for decades, although those battles seem to have done little to protect it from, as Eli Smith pointed out, a kind of slow sanitization. The Brooklyn Folk Festival feels like an unexpected haven for folk’s weirder, wilder, more diverse, and more provocative strains. It offers its own definition of the form.