His religious upbringing might well be as unorthodox as the psychedelic-inspired comic-strip characters that have made R. Crumb the most famous underground artist of his time.
Which, come to think of it, may have made Crumb the perfect artist for his latest project, an illustrated, comic-book version of "The Book of Genesis," the work that comprises the first 50 chapters of the Bible.
Raised in a secular household that was headed by a rigidly strict, ex-Marine father who was actually a closeted atheist, Crumb was sent off to Catholic school at age 6 because his father had always admired the discipline Catholic nuns were famous for instilling in their students.
"We never got a lot of religion at home," Crumb says of himself and his siblings. "But we certainly got the whole indoctrination and brainwashing in school."
Sixty years later, the creator of comic book characters like the R-rated Fritz the Cat and the bizarre Mr. Natural has finally put that religious training to good use.
"The Book of Genesis Illustrated by R. Crumb" was published last month, and on Oct. 24 the stunningly detailed, beautifully crafted black-and-white drawings that comprise its 201 pages will go on display at Los Angeles' Hammer Museum. After the exhibition closes in February it will move on to other cities, including New York and Portland, Ore., a circumstance that has the normally circumspect Crumb shaking his head in disbelief.
"The Bible! Jesus! Incredible," Crumb says in a voice filled with awe as he reflects on the project that has consumed the last five years of his life.
Indeed, the project does raise an obvious question: Why would the guy famous for drawing voluptuous women and nerdy looking, well-endowed men, who put the phrase "Keep on Truckin"' into the national vocabulary with his posters of a big-footed oddball out for a walk, and who by his own admission owes much of his artistic inspiration to his extensive use of LSD in the 1960s, take on the Bible?
"It's kind of complicated," Crumb guffaws during a phone interview from his home in the south of France.
"I don't think 'Genesis' is a good place to look for spiritual guidance or moral guidance," he continues. "I don't believe it's the word of God.
"At the same time," he continues, "I think the stories are very powerful. I'm not out to ridicule them or belittle them."
Although done in the same, unmistakable style that Crumb has brought to such comic books as Zap, Weirdo and Dirty Laundry, "Genesis" is also surprisingly respectful, as well as faithfully loyal to the Bible's original text.
"He could have done something really satiric but he didn't," says Ali Subotnick, who is curating the exhibit. "He's not bastardizing the stories at all."
Which is not to say Crumb hasn't added his own unique touch here and there.
While historical characters like Noah and the Pharaoh don't look that much different from how they have been portrayed by other artists, God and the serpent are another story.
Crumb's Creator is one mean-looking old dude, an angry, finger-pointing father figure with a flowing white beard and no sense of humor. The serpent, meanwhile, looks as much like a snake-oil salesman as a snake.
"He's a con man," Crumb says of the reptile that got Adam and Eve booted from the Garden of Eden. "The serpent represents that part of cleverness and persuasion and deception and flattery, all those qualities which humans are so good at but that we don't consider our finest virtues."
It was teachings like those that fascinated him and drew him to the project, Crumb says. He spent a couple of years doing the research before setting to work, secluding himself in a cabin in the mountains for weeks at a time so he could draw uninterrupted.
Not an atheist like his father, Crumb describes himself as a Gnostic, a member of that ancient movement searching for spiritual enlightenment.
"I've spent a lot of time studying different religious traditions and I meditate," he says. "I think that all humans have that need for some spiritual meaning.
"But," he adds with a hearty laugh, "I don't think you're going to find it in 'Genesis."'
Often described as reclusive, and by his own admission very shy, Crumb is actually an engaging conversationalist when he will sit down to talk. He's at turns witty, unpretentious and unfailingly friendly.
"Hi, I was just doing the dishes," he says upon picking up the phone. Minutes later, he lets out a loud, unembarrassed after-dinner belch.
The Philadelphia native has reluctantly agreed to come to the United States to promote the book and exhibition with a lecture at UCLA on Oct. 29 and a handful of other appearances. He says he's dreading all of them.
"I won't do TV," he adds flatly. "Don't want no cameras on my face. Hate that. Won't do it."
He is likely most recognizable from the 1994 documentary "Crumb" that showed him emerging from a frighteningly dysfunctional family to become a reluctant celebrity.
His older brother, Charles, who had inspired him to draw, committed suicide shortly after that film was completed. His younger brother, Max, also an artist, lives in seclusion, as does Crumb's son, Jesse. He speaks warmly of all three.
He fairly radiates with pride, however, at the mention of his daughter Sophie's name.
"She's a really good artist, in many ways she's a better artist than I am," he says. "But she's already feeling kind of self-consciousness about it because, being my daughter and all, she gets a lot of flak."
His wife, Aline, Crumb says, doesn't get the credit she's due as an artist. He says she's really the comedic force behind the pair's popular collaborative cartoons.
After he returns from the U.S., the pair plan to finish a forthcoming book.
After that: Who knows?
Crumb could return to more serious work, like the series of old-time musicians he admires that he profiled in the 2006 book "R. Crumb's Heroes of Blues, Jazz, & Country" or the illustrated version he did of 18th century essayist James Boswell's "London Journal."
Or he could just do something silly.
"I guess next I'll tackle the Quran. See how that goes over," he says, bursting out laughing.