“You’ve ruined my life,” Terry Zwigoff reports that Robert Crumb told him in a recent phone conversation. The source of Crumb’s distress is Zwigoff’s documentary, which bears the once-underground cartoonist’s last name and has generated acclaim and astonishment on the film-festival circuit for the last year. Now opening commercially, the film takes the raw, fetishistic work published under the name “R. Crumb” in such periodicals as Zap Comix and Mr. Natural and places it in the context of the artist’s life: parents, ex- and current wife, lovers, children, and—most arrestingly—his bizarre brothers Charles and Max.

“It’s excruciatingly embarrassing from the first frame to the last,” Crumb told Zwigoff of the film, which he finally watched on video at his home in the south of France. In reaction, the director notes, “He’s grown a long beard, he’s grown his hair long, he’s got this whole disguise.”

Crumb’s response “really shocked me,” says Zwigoff. “I didn’t really feel the film gave anything away he hadn’t given away in his comics.”

Despite Crumb’s comments, Zwigoff adds that “I can’t tell how he feels about the film.” He notes that Crumb’s published commentary, in a two-page strip he drew for the New Yorker, was kinder to the filmmaker than he had expected. “That guy’s a sadistic son-of-a-bitch when he wants to be,” Zwigoff admits.

Adding to the ambiguity is the cartoonist’s acceptance of an invitation to appear on Garrison Keillor’s radio show with his old-timey string band, the Cheap Suit Serenaders—whose bass player since 1973 has been none other than Terry Zwigoff.

The filmmaker is unconvinced that Crumb will honor the commitment. “He’s turned down everything he could do to promote this film,” Zwigoff says, refusing an appearance on David Letterman’s Late Show and an interview with Rolling Stone. “He was most upset because he saw a review in Sassy,” he notes.

Long before he began shooting Crumb in 1985, Zwigoff met Crumb because of another documentary, one about animal rights. “It was very radicalizing for me,” the director says of the film, which he saw soon after moving to San Francisco in 1970. “I stopped eating meat for about six years.” He also decided to publish an animal-rights comic book, and called Crumb to ask him to contribute. Of the cartoonists then prominent in the San Francisco area, Zwigoff declares, “He was far and away the best, in my view.”

The cartoonist’s reply, Zwigoff remembers, was cynical, but he ended up doing the cover anyway. Also contributing was Art Spiegelman, who turned in a short, early version of the strip that would become Maus. “Let’s see, the cats are Nazis, this is really lame,” Zwigoff thought. “I’m not going to print this”—but he did.

Crumb and the future filmmaker bonded when they found they shared a hobby, collecting old 78-rpm records of blues, ragtime, and country music. Asked to become the Serenaders’ bass player, Zwigoff accepted, even though all he could find to play was an abandoned cello. “I wanted to be in the band just to hang out with those guys,” he explains.

“I thought Crumb was a really important artist,” he says. “I think he’s one of the most important artists of this century.”

He was drawn to Crumb’s gift, he thinks, because “I can’t do anything well. That talent, that energy is mysterious.”

Reminded that he’s a musician himself, Zwigoff retorts, “A terrible musician. I’ve struggled for 25 years and I’m no better.”

In addition to being his bandmate and cinematic biographer, Zwigoff is still in a sense Crumb’s publisher. He’s in the process of packaging Crumb Family Comics, which will also include work by brothers Charles and Max, whose mental state has shocked some Crumb viewers. The cartoonist drew the comic’s cover in 1993, and the drawing (which is reproduced in the film’s press kit) suggests that Crumb had a pretty good hunch of how the documentary would be received before he ever saw it. He depicted himself at the center of his family, snarling, “Yeah, lock us all up!”

Despite this portent, Zwigoff says he’s puzzled by people who deem disturbing Crumb‘s portrait of Charles and Max. “I like them. I could relate to them,” he says of the brothers. “I think that kind of family is more common than people think.” He pauses. “Maybe that’s just the crowd I hang out with,” he adds.

“I hit it off with [Charles] right away,” says the filmmaker, who first met Crumb’s agoraphobic, heavily medicated older brother in 1974. “I felt bad for him, but I found what he was saying very funny. He was a cool guy.”

Zwigoff rejects the suggestion that the scenes that show Crumb giggling at Charles’ depressive rants capture the more famous brother’s callousness. “I was laughing too,” he says. “I’m sure Robert had a great deal of sympathy for Charles.”

“I admired very much [Crumb’s integrity]. Charles even had that more. I think that was why Robert succeeded and Charles didn’t.”

Indeed, Zwigoff says he made the documentary “to do something for Charles. I though this could maybe get him started again.”

For reasons best left to the film, that didn’t happen. But Zwigoff says the notoriety has helped Max. “You can see him becoming healthier. “People like my work?’ ”

That’s what Zwigoff thinks happened to Crumb, whose work is as satyrical as it is satirical. “His work began to be recognized,” Zwigoff theorizes. “He began to feel better about himself.”

Still, after Crumb’s experiences with Hollywood, whose version of his Fritz the Cat he abhorred, the cartoonist was unlikely to trust any old documentarian. “Nobody else could have made this film,” Zwigoff states matter-of-factly.

“I thought this film was amazingly commercial,” says Zwigoff, who had previously made a documentary, Louie Bluie, about an obscure blues musician. (Critics called it “delightful,” he remembers. “As a result, the theaters were empty everywhere it played.”) In L.A., however, he found that potential backers wanted to cut the footage of Crumb’s brothers and add animated segments. “They wanted this very upbeat film that I didn’t want to make. I liked the fact that [Crumb’s comics] were so dark.”

Finally, he found financing to complete the project. Too late, David Lynch decided to help; the director was so struck by Charles that he hoped to enlist him as an actor. Zwigoff no longer needed money, but he gladly added “David Lynch Presents” to the credits, although Lynch had nothing to do with making Crumb. Zwigoff finds the connection apt, noting that “Blue Velvet is probably my second-favorite film.”

With his documentary playing in only a few cities, Zwigoff is dubious that many Americans will claim Crumb as one of their favorites. Crumb’s fans, he says, “seem to hate the movie. People who don’t know anything about Crumb seem to like it more.”

Still, he notes that everywhere he goes, comic-book stores are sold out of Crumb’s work, and Last Gasp, the publisher of Crumb Family Comics, is pressuring him to finish the project. “All these comic publishers are desperate to cash in on this movie,” he says.

Reflecting on this, Zwigoff sounds rather like his longtime friend R. Crumb. “People are idiots,” he shrugs. “What can I tell you?”