In a previously unreleased album recorded on September 9 and 10, 2001, Carlin—shown above in April of that year—joked about Osama bin Laden, an exploding airplane, and his own fascination with disaster and death. Photograph by Paul Drinkwater / NBC / NBCU Photo Bank via Getty

On the nights of September 9 and 10, 2001, the comedian George Carlin performed shows at the MGM Grand casino, in Las Vegas, working through material that he planned to use at the taping of his next HBO special, in November. It was going to be called “I Kinda Like It When a Lotta People Die.” On the morning of September 11th, a lot of people did die. After 9/11, Carlin abandoned much of the hour he’d been working on and rewrote other parts, before taping the special, renamed “Complaints and Grievances,” at the Beacon Theatre, in New York. That fall, at a time when many comedians were struggling, often publicly, with questions about how or when to be funny, there were some things, it seems, that even the combative Carlin considered off-limits.

Those original September sets were lost—save for their place in the memory of the audiences in Vegas, who must have woken up to the news on 9/11 with an especially eerie feeling—until cassette recordings were discovered, a few years ago, in Carlin’s archives. Now, fifteen years after the attacks, and eight years after Carlin’s death, material from the two nights has been arranged in a new album by his daughter Kelly, his longtime manager and confidant Jerry Hamza, and an archivist named Logan Heftel. It is available now, under its original title, on Sirius XM, and out on CD and for download next week.

The most striking thing about the show is that Carlin made a joke about Osama bin Laden and an exploding airplane. In a fashion typical of the comedian, who always passed easily between the corporeal and the sublime, it started as a fart joke. “These planes get flying so fast that all the most vicious, lethal, volatile, flammable, unstable farts get pushed toward the back of the airplane, where they begin to build up pressure,” he said. “And they build, and they build, and they build until they reach critical fart density—C.F.D.—and they continue to build throughout the flight, until finally some kid turns on a Game Boy and boom! The whole back end of the plane blows off. And you know who gets blamed? Osama bin Laden. Terrorists get blamed for these explosions that are nothing more than cabbage-fart detonations.” As extravagantly silly as the bit is, it’s clear why Carlin decided to put it away.

The album’s climax explores an idea that would have been no less incendiary in the months after 9/11. What Carlin really likes, he tells the audience, are “big, fatal disasters with lots of dead people.” As in his best work, Carlin luxuriates in the cumulative effect of lists, running off his favorite forms of cataclysm, from the global to the absurdly specific: earthquakes, tornadoes, airplane crashes, “food poisoning at a church picnic,” “a runaway merry-go-round.” He launches into a wild, extended riff—one that he would later repurpose in his 2006 special, “Life Is Worth Losing”—about a broken water main in Los Angeles setting off a cascading series of increasingly gruesome disasters across the country and, later, the world, which ends in a surreal new universe in which what he calls “trillions of Uncle Daves,” stand-ins for all the angry white men in America who felt the system had been rigged against them, are finally happy. “I’m always rooting for a really high death toll,” he says.

Toward the end of the album, Carlin implicates the audience more clearly in his death obsession. “I know some people think these kind of thoughts are ghoulish and demented and sick, but I know they’re not,” he says. “I know these things are normal and quite common. . . . Society has told you that nice people don’t take pleasure in mass death. But you’re wrong, because I think mass death is terrific, and I’m a really nice fucking guy.” Speaking in a menacing, devilish growl, Carlin gives voice to a dark part of us that eagerly, and at times almost giddily, consumes the wall-to-wall media coverage that certain kinds of mass-death events generate. “The only thing I care about is fun. That’s all. Entertainment,” he says. He explains the excitement he feels when watching fatal disasters as a visceral, animal response. The appeal he is making to members of the crowd, as he is getting them to laugh, is to consider this almost reflexive fascination, and to deny even a germ of it in themselves.

Carlin’s sets in Vegas were not, of course, his response to September 11th. By the time of his HBO special, that November, he had given up most of the death-obsessed bits in favor of a no less hilarious, though certainly safer, set based on the types of people who really pissed him off—rich guys in hot-air balloons, gun nuts, guys named Todd. Still, onstage in New York, he didn’t ignore 9/11 completely. He told members of his audience that he had to bring it up to get it out of the way so that they might have some fun, because, he said, adopting a mock stentorian voice, “otherwise, the terrorists win.” He offered a riff on that ubiquitous phrase, while lamenting the fact that patriotism and consumerism had been so readily conflated. Carlin couldn’t have been surprised by this development—he had been telling angry jokes about this American impulse for, by that time, more than thirty years. September 11th was, Carlin said, like the elephant in the room or the “turd in the punch bowl”—it needed to be dispatched before the comedy might move on. He even offered a sarcastic capitulation, saying that tough times required you to cozy up to “people you don’t like, people you don’t trust, people you don’t respect”—in his case, the United States government. It got a big laugh, and seemed to signal that, on the subject of 9/11, he would not be making anyone too uncomfortable.

Any lost performance, once it is dusted off and released to the public, seems to exist out of time. It is both old, a capsule of the moment when it was recorded, and new, and thus heard in the context of the present. Carlin’s Las Vegas shows, especially, register in several time zones at once, acting as a kind of provocative before-the-fact commentary on the stories the country would tell itself about the 9/11 attacks, and the kinds of violence that have plagued Americans in the decade and a half since. At one point in his routine, Carlin laments that the United States has “turned into a nation of rats and squealers,” who, to his immense disgust, have come to venerate, trust, and coöperate with the police. “You don’t help the police,” he says. “They’re not on your side.” In a riff that explains why he has always rooted for crooks, he lists instances of malfeasance by the cops—planting evidence, using excessive force, targeting minorities. It’s hard to imagine him getting this bit across at the Beacon, in the fall of 2001, when N.Y.P.D. hats were still selling fast on the streets outside. But, listening today, it seems not a moment too soon.