'Who do you think made the first stone spear?" asks Temple Grandin. "That wasn't the yakkity yaks sitting around the campfire. It was some Asperger sitting in the back of a cave figuring out how to chip rocks into spearheads. Without some autistic traits you wouldn't even have a recording device to record this conversation on."

As many as one in 110 American children are affected by autism spectrum disorders, according to the Centers for Disease Control. Boys are four times more likely to be diagnosed than girls. But what causes this developmental disorder, characterized by severe social disconnection and communication impairment, remains a mystery.

Nevertheless, with aggressive early intervention and tremendous discipline many people with autism can lead productive, even remarkable, lives. And Ms. Grandin—doctor of animal science, ground-breaking cattle expert, easily the most famous autistic woman in the world—is one of them.

Earlier this month, HBO released a film about her to critical acclaim. Claire Danes captures her with such precision that Ms. Grandin tells me watching the movie feels like "a weird time machine" to the 1960s and '70s and that it shows "exactly how my mind works."

At the Manhattan screening I attended, Ms. Grandin was dressed in her trademark look—an embroidered cowboy shirt, in this case brown with a red neck kerchief—and was holding forth confidently, cracking self-deprecating jokes. Parents of children with autism thanked Ms Grandin for her books; she's the reason they can relate to their children. Teachers asked for specific recommendations: How can they capitalize on their autistic students' obsession with dinosaurs? A boy, perhaps 10 or 11, sought Ms. Grandin's advice on how to deal with the bullies that pick on his nonverbal brother.

Zina Saunders

Her cadence is unusual, staccato-like, and her pale blue eyes sometimes drift off into the distance. But she seems a different person from the young woman in the film, for whom being hugged, let alone schmoozing at a cocktail party, seemed physically painful. What's changed?

"The thing about being autistic is that you gradually get less and less autistic," she says, "because you keep learning, you keep learning how to behave. It's like being in a play; I'm always in a play."

Her rehearsal began early and in earnest. Born in 1947, she did not speak until the age of four. All of the doctors recommended permanent institutionalization; her father agreed.

But her mother refused and hired a speech therapist and a nanny who spent many hours a week taking turns playing games with her daughter. She insisted that Temple practice proper etiquette, go to church, interact with adults at parties. "I'd be in an institution if it wasn't for her," Ms. Grandin says.

She has always thought socializing was boring, and she famously described herself as "an anthropologist on Mars" to neurologist Oliver Sacks when explaining her interactions with typical people. As a teenager, while her peers fixated on boys and pop culture, Ms. Grandin was consumed with scientific experiments.

Her first major invention, at 16, was a "squeeze machine"—a device she modeled on the squeeze chutes used to restrain cattle that she first saw on her aunt's ranch in Arizona. "I noticed that when the cattle got into the squeeze chutes they got calmer," she says, "so I built a plywood device I could get into that was similar, because I had these horrible, horrible anxiety attacks." The physical pressure calmed her tremendously.

These days, Ms. Grandin is known as much for her professional work—she revolutionized livestock handling equipment—as for her expertise on autism. "I've always thought of myself as a cattle handling specialist, a college professor first; autism is secondary," she says. But she does credit her autism for her unique ability to relate to cattle.

Ms. Grandin wondered what made the animals moo and balk. Kneeling down to see things from a cow's eye view, she took pictures from within the chutes.

She found cattle were highly sensitive to the same sensory stimulants that might set off a person with autism, but were inconsequential to the average handler. They were shockingly simple revelations: light and shadow would stress the animals, as would grated metal drains. Prodding and hollering from cowboys, intended to move cattle along, only alarmed them further.

Her designs reflected these insights. A curved, single-file chute mimicked the cattle's natural tendency to follow each other. She replaced slated walls with solid ones to prevent cattle from seeing the handlers and cut down on light and shadow.

Today, half of the cattle in this country pass through the slaughter systems that Ms. Grandin invented. She's a consultant to companies like McDonalds and Burger King. Yet—and she might well be the only person with these two associations—she's also been honored as a "visionary" by PETA for making slaughterhouses more humane.

When Ms. Grandin isn't teaching at Colorado State University, she's traveling the world lecturing or promoting her (10) books. Whether discussing animals or autism, though, she always comes back to the defining feature of her mind, the characteristic that allowed her to create such accurate equipment designs: she literally thinks in pictures.

Nancy Minshew, a professor of neurology at the University of Pittsburgh, conducted tests on her brain that showed a "gigantic, huge trunkline going back into the primary visual cortex," Ms. Grandin says. Translation for the layperson: "I basically have a gigantic graphics card."

So when Ms. Grandin says "Google me," as we sit down for a more intimate conversation after the film, she's not suggesting I look up the half-million references to her on the Web. She's challenging me to test her photo-realistic brain. "And don't pick something easy like house or car," she instructs.

Ok, how about love? "Herbie the Lovebug. My mother." God? "I've got this Hubble Space telescope poster of 100 galaxies." What about something even more abstract, like responsibility? "I see people that have done bad things with terrible consequences: Michael Vick. Tiger Woods. Bill Clinton."

People on the "spectrum" tend to be just as obsessed with things and the way things work as they are uninterested in social relationships. And, as Ms. Grandin observed, people interested in things make important advancements—particularly in engineering, science and technology.

Which is not to say she romanticizes this disorder. The politics around autism are fraught with landmines, and Ms. Grandin follows the issues very closely. She approaches them like the scientist she is: exacting, realistic, pragmatic. What sets Ms. Grandin apart is that she knows what autism feels like, and, unlike so many others with the disorder, she can articulate it.

Last week, the American Psychiatric Association unveiled its proposed revisions to the DSM (Diagnostic and Statistical Manual of Mental Disorders), the bible of the field. Up for revision are Aspergers and autism. The association recommends scrapping both and replacing them with the umbrella label of "autism spectrum disorders."

"From a scientific standpoint, Aspergers and autism are one syndrome," Ms. Grandin says, reflecting the scholarly consensus. "Aspergers is part of the autism spectrum, not a separate disorder." But "the problem is you have a whole lot of people that have labels and identify with the label."

Perhaps more significantly, earlier this month Britain's esteemed medical journal, The Lancet, formally retracted its 1998 paper that linked vaccinations to autism. That paper, whose primary author was Dr. Andrew Wakefield, studied 12 children who exhibited autistic behaviors. The authors suggested they were caused by the measles-mumps-rubella vaccine. The paper set off a firestorm, fueling the antivaccine movement perhaps best associated with the actress Jenny McCarthy, whose son is autistic.

"Scientifically, there's still some things to be done," Ms. Grandin says. Scientists need to study "the kids where they seem to have language and then they lose it at 18 months to two years of age." She adds: "I've talked to too many parents that have talked to me about regressions that I can't just pooh-pooh that off."

But, she adds emphatically, this does not mean parents should stop vaccinating. "We can't stop vaccinating because we're going to end up with all these childhood diseases. I mean, I grew up with iron lungs. . . . That was horrible, dreadful . . . We can't go back to that."

So what does she recommend? "If you have autism in the family history," or other auto-immune problems, "you still vaccinate. Delay it a bit, space them out." There is, she says, a "strong genetic basis" for autism, and she has a "very typical family history" that includes anxiety and depression on both sides of the family, intellectual giftedness, lots of food allergies and engineers ("my grandfather was an engineer who invented the automatic pilot for airplanes"). This is why, she says, "there tends to be a lot of autism around the tech centers . . . when you concentrate the geeks, you're concentrating the autism genetics."

Many talk of an autism epidemic—has there been a spike in autism lately? "You know the geeks have always been here. They used to call them geeks, nerds and dorks. Now they're getting labeled Aspergers—there's just a point where it's just normal personality variation."

But, Ms. Grandin adds, "some of the severe autism has increased." As to what is causing it, she mentions the possibility of environmental toxins interacting with "susceptible genetics." A study released last week by researchers at the University of California, Davis, found that women over the age of 40 who give birth are twice as likely to have a child with autism as those under 25.

While she's adamant that there is no magic cure for this disorder, Ms. Grandin says she has seen some "very big improvements" with special diets, like wheat-free and dairy-free. She says the low doses of antidepressants she's been on for over 30 years are "magic," and have saved her from constant panic attacks and anxiety.

Mostly, though, her advice is simple: It's about hard work. Young children need 20 or 30 hours a week of one-on-one time with a committed teacher or mentor. Money, Ms. Grandin says, should not be an obstacle. If you can't afford a professional teacher, find volunteers through your church or synagogue, she says. Parents need to teach 1950s-style social rules "like please and thank you, basic table manners, how to shop."

There have to be high expectations. She's worried about the "handicapped mentality" that she thinks is increasing. "When I see these kids with 150 IQ and their parents want to put them on Social Security [disability], it drives me nuts." These kids "will come up to the book table and start talking about 'my Aspergers.' Why don't you talk about becoming a chemist, or a computer programmer, or a botanist?"

She continues: "It's important to get these autistic kids out and exposed to stuff. You've got to fill up the database." Silicon Valley and the tech companies are like "heaven on earth for the geeks and the nerds. And I want to see more and more of these smart kids going into the tech industry and inventing things—that's what makes America great."

Ms. Grandin lives in a simple apartment in Fort Collins, Colo., and has used the profits from her books to put students through school. "Four PhDs I've already done, I'm working on my fifth right now. I have graduate students at Colorado State—some of them I let in the back door, like me: older, nontraditional students. And I've gotten them good jobs."

"You know what working at the slaughterhouses does to you? It makes you look at your own mortality."

"When I was younger I was looking for this magic meaning of life. It's very simple now," she says. Making the lives of others better, doing "something of lasting value, that's the meaning of life, it's that simple."

How about meaning, I ask. What's the picture for that word? "Ok, now I'm seeing a mother saying your book helped my kid go to college—that's meaning. Or my kid got a job because of one of your lectures—that's meaning. Or a rancher comes up and says that piece of equipment works really well—that's meaning. Concrete, real stuff. On. The. Ground."

Ms. Weiss is an assistant editorial features editor at the Journal.