Even the title is something of a joke, first uttered by Mr. Markey, a director in Los Angeles who had flown to London with Nirvana that August. (“Those guys had just been up all night shooting the video for ‘Smells Like Teen Spirit,’ and I think Kurt had clashed with the director.”) As Mr. Markey recovered from jet lag with members of Sonic Youth at a hotel in Ireland, they watched Mötley Crüe on MTV playing a cover of “Anarchy in the U.K.” by the Sex Pistols. “And I just said, ‘1991 is the year punk broke,’ ” Mr. Markey recalled. “They kind of snickered, and from there we all started saying it to each other.”

Proudly self-marginalizing, the notion of punk ever breaking out seemed absurd. “Sonic Youth had already witnessed the commercial failure of the Replacements and Hüsker Dü,” Mr. Markey said, in a telephone interview. But Sonic Youth was opening arena shows for Neil Young earlier in the year, and most of the other bands on the circuit — like Dinosaur Jr., Mudhoney, Babes in Toyland and Gumball — were also playing to the largest audiences of their careers. Sonic Youth’s noise rock had found a home on a major label, DGC, and the group had convinced Nirvana to sign as well. Still, the musicians anticipated nothing more than a slightly easier ride after touring by van in the ’80s.

“I guess we never expected that just around the corner there was this other level of success for a band that came out of our scene,” Mr. Ranaldo said.

Part of the fascination with “1991: The Year Punk Broke” is that we know the seismic changes about to happen to the musicians. “It’s almost like watching the moment before a car crash,” Mr. Young said. Cobain, just three years from his death at the age of 27, hardly seems destined or doomed. He spends most of his time mugging for the camera with the energy of a child at a rollicking birthday party.