It is no secret that David Lynch, the writer-director-composer-painter, has an unusual relationship with Bob's Big Boy restaurant. For seven years in the 1980s he ate lunch there every day, ordering cup after cup of oversweetened coffee and a single chocolate milkshake while scribbling notes on Bob's little square napkins.

What is not widely known--and what reveals something fundamental about the 53-year-old filmmaker--is that during this period, back when he "thought that sugar was really a beautiful thing" (he doesn't eat it anymore), he took pains to arrive at Bob's at precisely 2:30 p.m. each day. The reason: It increased the odds that he would encounter perfection.

"If you go earlier, at lunchtime, they're making a lot of chocolate milkshakes. The mixture has to cool in a machine, but if it doesn't sit in there long enough--when they're serving a lot of them--it's runny," he said. "At 2:30, the milkshake mixture hasn't been sitting there too long, but you've got a chance for it to be just great."

Lynch's reward for this meticulous preparation was minimal: only three perfect milkshakes out of more than 2,500. But that wasn't the point. For Lynch, it was enough to know he had set the stage for excellence to occur. Lynch thinks a lot about this idea, which affects not just his diet (he still eats the same thing, every day, for lunch and dinner), but also his preference for sparse furnishings and his Zenlike approach to choosing projects. Whether with milkshakes or movies, Lynch believes you must make room for inspiration to strike--to lay the proper groundwork for greatness to take hold.

So he seems particularly pleased with "The Straight Story," his eighth feature film, which arrives in theaters Oct. 15. Based on the true story of Alvin Straight, a 73-year-old Iowa man who rode a lawn mower 350 miles to see his ailing brother, the script caught Lynch's attention, held it and wouldn't let it go. The result: Three years after his last film ("Lost Highway"), and nine years after his hit TV series "Twin Peaks" introduced his eccentric vision to mainstream America, Lynch has completed a movie unlike any he has made before.

For one thing, "The Straight Story" marks Lynch's first time directing a project he did not write (Mary Sweeney, Lynch's longtime editor and companion, and John Roach share writing credit). The film, which stars Richard Farnsworth as Straight and Sissy Spacek as his daughter, Rose, is not populated by the misfits and mutants whom Lynch fans have come to know in films such as "Eraserhead" and "Blue Velvet." Instead, it celebrates decent Midwestern folk, many of them elderly.

Most surprisingly, the movie--which is being released by Walt Disney Pictures under its family-friendly Disney banner--is rated G.

Lynch knows some people will call this a departure for him.

"When you've done two or three films that first got an X and finally got an R and then you do a G-rated film, it's kind of considered to be a different kind of thing for a person," he acknowledged one morning recently with an understatement that sounded, appropriately, Midwestern. (Lynch himself grew up in Missoula, Mont.)

Welcoming a visitor to his Hollywood Hills home, Lynch sat in a low-slung chair in a nearly empty room that he laughingly asserted was still too cluttered.

On a purely visual level, "The Straight Story" is a loving portrait of American farm country. Rarely have endless rows of corn been so embraced by a camera. But among the windmills and silos, bleached-out barns and harvesting machinery, there are also images that will warm the hearts of die-hard Lynch fans: an ample woman on a plastic lawn chair, for example, sunning herself with a metallic reflector while biting into a pink Sno-ball.

Much has been written about the link between Lynch's formal training as a painter and the vivid imagery of his films. But Lynch is the first to say that his movies bear little resemblance to his canvases. He sees more connection between filmmaking and musical composition, with which he also enjoys experimenting (often in collaboration with Angelo Badalamenti, who has created music for every Lynch project since 1986).

Not surprisingly, then, "The Straight Story" is also a striking aural experience. In addition to directing the film, Lynch is credited as its sound designer, and even casual viewers will notice the care he has taken to stimulate the ears as well as the eyes. Whether it's the whir of a grain elevator, the crash of a lightning storm or the whiz-whoosh of cyclists on a country road passing at close range, the film serves up the audible textures of life in the heartland.

"Film to me is like music in the way it deals with things happening in sequence. Certain events have to precede others in a certain way for it to work. But there's a connection between music, film, painting, writing, everything," said Lynch, who does all those things while also making and designing furniture and raising his and Sweeney's 7-year-old son.

Lynch's cinematic power first struck the public's fancy in 1977 with the release of "Eraserhead," a surrealistic nightmare about a couple raising a mutant baby. The unsettling film, whose main character fantasized about having his head used as an eraser, would become one of the most successful midnight movies on the cult circuit.

"Eraserhead" also impressed comedian Mel Brooks, whose company was producing a film about John Merrick, the so-called Elephant Man whose deformed head and body masked a gentle soul. Brooks hired Lynch to write and direct the black-and-white "Elephant Man." After its release in 1980, it was nominated for eight Academy Awards, including one for Lynch for best director.

Suddenly, Lynch was on the A-list. But he was more interested in pursuing his own projects than in making big Hollywood pictures. He worked on his own small film, "Ronnie Rocket," at Francis Ford Coppola's Zoetrope Studios.

When Zoetrope's financial woes forced Lynch to suspend production, however, he signed on with producer Dino De Laurentiis to make his first big-budget film: the long-anticipated screen version of "Dune," Frank Herbert's best-selling sci-fi novel. It was a huge undertaking--Lynch himself winnowed the 500-page tome into a script that tried to make cinematic sense of Herbert's complex vision, and employed 20,000 extras to try to bring it to life.

The result: mixed reviews, disappointing box office and what Lynch would later describe as "a tremendous amount of pain." Devastated by his failure to bring "Dune" to life in a comprehensible way, he sought solace each day at Bob's Big Boy.

"The coffee and the sugar would really get me going. And I would try to catch ideas," he said the other day, explaining that the daily routine helped him think in much the same way that uncluttered spaces do. "The more things you have in a room, it does something to the mind. "

Apparently, Lynch was onto something, because his next film--mapped out, at least in part, on Bob's napkins--was "Blue Velvet." Heralded by Newsweek as "a breakthrough, fusing [Lynch's] most personal obsessions with sex, death and innocence with a mystery story," the movie followed an amateur sleuth (Kyle MacLachlan) on a search for the owner of a human ear (found in a field) that leads him into a dark underworld of drugs, corruption and sexual violence. Once again, Lynch received an Oscar nomination for best director.

Since "Blue Velvet," Lynch has made the initially popular TV series "Twin Peaks" (and the less than popular feature film based on it, "Twin Peaks: Fire Walk With Me"), two more feature films ("Wild at Heart" in 1990 and "Lost Highway" in 1996) and a few other forays into television.

But "The Straight Story" intrigued him in a new way, he said, because it posed a challenge: capturing on film the content of a man's heart.