Richard Matheson‘s novels and short stories have been adapted into television programs, films, television programs that have subsequently been adapted into more films, comics, literature, et cetera. Even if you’d never heard of Matheson before he died last month you’ve probably seen something stemming from his inscrutable mind. Matheson often penned his own adaptations, as well as original scripts, notably turning eight of his stories into Twilight Zone episodes, but only one of Matheson’s adaptations really captures the inherent sense of isolation and loneliness, of questions spurring more questions and answers as opaque as oil, so replete in his writing.

Matheson and ABC producer Lillian Gallo took the former’s story “Duel”, which appeared in Playboy in 1971, and turned it into 74 minutes of small-screen tension. It was a surprise hit and nabbed a nomination for Best TV Movie at the ’72 Golden Globes, so producers, hoping television popularity would translate into big-screen bucks, asked their first-time director, a young Jewish boy from Los Angeles named Steven Spielberg, to add sixteen minutes of new footage, and a few naughty words to act as a vulgar veneer, so that Duel could be released in theaters.

The film’s irregular path to theaters is more complex than the actual film: our Everyman (Dennis Weaver) is chased on a two-lane California road by a 1960 Peterbilt 281 tanker. We never see the insidious vehicle’s driver just clastic cuts to his hands and his boots.

As with the big fish prowling the shallow shores of Amity Beach in Spielberg’s later film, Jaws, the terror of the rusty rig lies not within its oddly deft ability to find and chase unwitting prey, but in the enigmatic nature of the attacks. Why is a 25-foot shark attacking little boys in 3-feet of water? Why is a nameless, faceless apparition in a tanker chasing a poor demotic guy across a desert? You can ask, but Matheson and Spielberg eschew whys and deal strictly in grueling suspense.

Matheson’s writing is, at its best, lean enough to be accessible but dense enough with metaphysical monsters and borderline-existentialist musings to spur cogitation. He uses ambiguity as a weapon and offers faux-closure, giving his audience a discernible ending but leaving them alone in a swirling benthos of opacity. His novel I Am Legend, adapted for film three times and not once with enough dexterity to emulate Matheson’s deeper paranoia, ends with the hero introspectively commenting on the utter irony of his own demise: he was determined to cure a vampiric disease and eradicate the threat to his own existence but he ends up becoming the outlier, the Other, and the Diseased collate into something resembling a ghoulish community and execute him. He can’t condemn the ghouls, though–he’s become a disease to them, a threat to their existence and they have to eradicate him.

The poignancy of the novel is completely lost when you put Chuck Heston in your lead role, or have Will Smith martyr himself to save humanity. This is why Duel remains the best Matheson adaptation. Our non-hero survives, and he watches the big scary tanker plummets off a cliff and explodes, but he doesn’t win: staring into a dusty abyss as the sun clings low to the horizon, the Everyman is plagued by paranoia. He will never know why a tanker chased him across the desert.