On a recent breezeless afternoon, I met two young Saudi women sitting on the grass outside the Prospect Park Bandshell, in Brooklyn. They were wearing T-shirts emblazoned with the logo of the Lebanese alternative-rock band Mashrou’ Leila, and they were snapping selfies where the band was scheduled to headline at the bric Celebrate Brooklyn! Festival later that evening. “Do you think the show’s been cancelled?” one of the women asked. Nearby, picnickers stoked their barbecues and a child’s birthday party was under way. Sara and her friend Nauf had rerouted their vacation for the concert. When I assured them that the band was already on site, they hopped up and down in excitement.

Mashrou’ Leila, the biggest alt-rock band in the Middle East, was formed in 2008 by several students at the American University of Beirut. The group’s early songs—ironic, grungy jams about the nettlesome oppression of bourgeois Lebanese society—made them famous in Beirut’s indie scene. Later, during the Arab Spring, they found a regional audience with songs about quotidian life in Beirut: busybody gossip about couples on the boardwalk, the bored soldier hassling young men at a checkpoint, the social pressure to marry someone from your own sect. Hamed Sinno, the band’s lead singer and lyricist, may be the most prominent gay musician in the Arab world, and much of his songwriting takes aim at homophobia and misogyny. As the group’s stature has grown, so have the concerns of the authorities in many countries where they play. “Even the international labels who approached us for the last album wanted to censor a lot of the content, like the album art, and to get rid of one of the tracks,” Haig Papazian, the band’s violinist, told me shortly before the Brooklyn show. “They were worried it wouldn’t sell in the Middle East.” Sinno added, mimicking a nasal-voiced marketing executive, “They’re, like, ‘We really want to showcase that you guys are from different sects.’ Or: ‘Maybe tone it down with the gay stuff? Simplify your lyrics. Try this in more Egyptian dialect. . . .’ ”

The album in question, “Ibn El Leil” (“Son of the Night”), is a departure from the band’s earlier material, combining slippery bass grooves with lush, cinematic synths and Papazian’s haunting violin melodies. It’s a sound reminiscent of the E.D.M. playlists of Beirut’s famous night-life scene. For Sinno, the night club is the city’s premier site of political and philosophical debate—the equivalent of an Ancient Greek agora. “That’s what a club is in Lebanon,” he said. “It’s just where the city goes at night.” The gains made for gay rights and gender equality in recent years have been worked out, he said, in bars and discothèques. “The fact that gay men feel more comfortable going out in certain places in Beirut and holding hands or making out on a dance floor says a lot. All of that is political negotiation in the absence of a structure that is doing that negotiation for you.”

Mashrou’ Leila is known for its erudite, often enigmatic, lyrics, and “Ibn El Leil” is the band’s most allusive effort yet, with copious references to Greek mythology, ancient poetry, and pagan ritual. When I asked the band members whether I’d correctly identified a quote from Walt Whitman, they peppered me with other literary inspirations that appear on the album: Abu Nuwas, Sappho, Allen Ginsberg, Shakespeare. Unsure of what to make of a reference to mushrooms and the Bible in the chorus of “Tayf” (“Ghost”)—a song about a gay club in Lebanon that was shut down by the authorities—Sinno explained, “It’s from Sylvia Plath’s poem ‘Mushrooms,’ one of the most incredible feminist texts I’ve ever read. It’s really beautiful.” Abou Fakher, the band’s guitarist, speculated that for much of its fan base, especially outside of Lebanon, the band’s appeal has to do with the energy and spectacle of the show rather than with the lyrics. “But if someone really wants to get what you’re talking about, they just Google it,” Sinno added.

Several hours later, while watching from backstage, I spotted the two Saudi fans, who’d made it to the front row, pushing up against the barriers. They both reached up into the air and danced as Sinno segued from “Aoede,” an ode to the Greek muse of voice and song, into “Ala Babu” (“At His Door”), which he once described as being “about really good sex.” In the ochre wash of the stage lights, only the first few rows of the diverse audience were visible, but I could hear them singing.