Alcoholism, sectarian animus, abandonment, and abuse are no strangers to Irish cinema. But though these themes frequently make for sodden bathos, the music-themed documentaries in the fourth annual Boston Irish Film Festival respond with eloquent remonstrance, playful defiance, and canny reversals of adversity.

Freedom Highway (April 27 at 2 p.m. at the Harvard Film Archive), Philip King’s history of the protest singer, isn’t strictly about Ireland but does offer a fresh look at a nation where music has been central to protest for centuries. We hear Derry civil-rights marchers borrowing "We Shall Overcome" from Selma. We find Karan Casey dedicating Woody Guthrie songs to asylum-seeking emigrants who come to the new Ireland and meet with racism. We see Bono inviting the mothers of Chile’s "disappeared" on stage as he channels Pinochet-murdered folksinger Victor Jara. These conflations of Irishness with the world’s struggles evoke a kind of pan-global empathy with the dispossessed.

Tom Collins’s Teenage Kicks: The Undertones (April 27, at 6 p.m. at the HFA) profiles five misfits from Derry’s Bogside neighborhood who had no use for protest songs. Instead, as a war raged, they seditiously bashed out exuberant punk-pop anthems. Hearing "Teenage Kicks," seven chords of keening adolescent libido, played over footage of rumbling tanks and petrol-bombed cars makes the point. But despite their fame abroad, the Undertones were "surrounded by animosity, even contempt" in their own neighborhood for not enlisting in the "Bogside struggle." (Seeing "The Undertones" emblazoned on a wall, some wag scrawled the prefix "hang.") Collins’s film is an inspiring look at a band whose odes to summertime and Mars bars were a tiny rebuke to the murderous acrimony that surrounded them. "For us," says singer Feargal Sharkey, "getting on stage was pure, utter escapism."

The subject of Sarah Share’s If I Should Fall from Grace with God: The Shane MacGowan Story (April 27 at 9:30 p.m. at the HFA) also has a predilection for escapism — the bottled kind. "I’m all that stands between the death of Irish culture," MacGowan slurs, "and the life of Irish culture." A gifted songwriter with a knack for fusing the romantic and the debauched, MacGowan has revitalized Irish music — in his way. But his aura of massive dissolution also typifies the worst Paddy stereotypes. Share strips away the caricature and finds MacGowan’s big, drunken heart.

Certain moments are illuminating: Shane the toddler with a Guinness at his lips; Shane flirting with swooning old ladies; Shane telling girlfriend Victoria that his love for her "can’t be explained in words . . . maybe in Irish it could be." Footage of vigorous early Pogues gigs set against recent interviews with a bloated, toothless man wrestling thoughts from an inebriated fog does throw the damage done into stark, sad relief. But the sublimely tarnished songs somehow keep getting written. "It’s my fucking life," MacGowan mutters, and you have to give him that. "People often ask what Shane would be like if he didn’t drink," says Victoria, "but it seems like that’s almost his purpose in life. To write songs about drinking." Dum vivimus vivamus.

Whereas the MacGowan and Undertones documentaries assume some received knowledge about their subjects, none is needed for Shimmy Marcus’s brilliant, tragicomic Aidan Walsh: Master of the Universe (2000; April 27 at 4 p.m. at the HFA), a moving paean to Dublin’s original musician-entrepreneur-Venusian that Irish music rag Hot Press rightly calls "the best documentary since Crumb." When speech-impeded Aidan got a fluke record deal on the strength of his loopy version of "The Hokey Cokey," he knew he’d soon be "bigger than the Beagles!"

Not quite. Thanks to a cadre of media boosters and an outlandish self-made mythos, Aidan was soon rather famous — in Dublin, at least. But the emotional crux of Marcus’s tale lies in how apple-cheeked Aidan bests his sorrowful childhood. When he was a boy, his "mudder disappeared from the planet of Earth." Marcus returns with him to his orphanage, where Aidan guilelessly recalls the priests who raised him: "some of dem were good, but lot of them are hyp’crites. Dey’d rape you tru the week then go to Mass on Sunday." And Aidan never found his ma. A camera poignantly pans around his kitsch-choked room, lingering on a bas relief from the Stations of the Cross: "Christ Meets His Mother." Yet despite these moments of pathos, Aidan’s is an exultant life. Deprived of family, he parlayed a little serendipity and an ebullient personality into an adulatory cult following. Call it the pluck of the Irish.

For the complete festival program, visit http://www.irishfilmfestival.com/