His death was confirmed by his son Richard Christian, known as R. C.

Mr. Matheson had a prolific imagination for the "what if?" story, and he drew his ideas from both actual events and other stories. After the unsettling experience of being tailgated by a truck driver, he wrote the short story "Duel," about a motorist who is relentlessly stalked in a highway chase by a tractor-trailer, its driver unseen. The story became the basis for Steven Spielberg's first feature film, starring Dennis Weaver.

An early novel, and perhaps his best-known work, "I Am Legend," about the last surviving human in a world in which everyone else is a vampire, was published in 1954 and adapted in 1964 as "The Last Man on Earth" with Vincent Price, in 1971 as "The Omega Man" with Charlton Heston and in 2007 as "I Am Legend" with Will Smith.

Mr. Matheson was inspired to write it while watching the 1931 film version of "Dracula."

"My mind drifted off, and I thought, 'If one vampire is scary, what if the whole world is full of vampires?' " Mr. Matheson said in an interview with the Archive of American Television. In a widely distributed statement, Stephen King, who acknowledged Mr. Matheson as an influence, said: "Matheson fired the imaginations of three generations of writers. Without his 'I Am Legend,' there would have been no 'Night of the Living Dead'; without "Night of the Living Dead,' there would have been no 'Walking Dead,' '28 Days Later' or 'World War Z'."

Mr. Matheson's 1956 novel "The Shrinking Man," a frightening fantasy about a man whose simultaneous exposure to insecticide and radioactivity causes him to dwindle gradually in size, was adapted twice for the movies — once as a horror story, "The Incredible Shrinking Man" (1957), and once as a comedy starring Lily Tomlin, "The Incredible Shrinking Woman" (1981).

In the late 1990s two of his books, "A Stir of Echoes," a ghost story, and "What Dreams May Come," about a man adrift in the afterlife, were also made into feature films, starring Kevin Bacon and Robin Williams respectively.

Another novel, "Hell House" (1971), about four people investigating paranormal activity in what one character describes as "the Mount Everest of haunted houses," became the 1973 film "The Legend of Hell House," starring Roddy McDowall. The book showed off Mr. Matheson's gift for creepy atmospherics.

"Edith turned and saw a body of water ahead, a gravel path curving to its left," Mr. Matheson wrote, describing a character's first approach to the house. "The surface of the water looked like clouded gelatin sprinkled with a thin debris of leaves and grass. A miasma of decay hovered above it, and the stones which lined its shore were green with slime."

Mr. Matheson sometimes wrote the screenplays for the adaptations of his books, including "Duel" and "The Legend of Hell House"; he adapted Edgar Allan Poe stories for several films, including "House of Usher," "Pit and the Pendulum" and "Tales of Terror"; and he wrote the screenplay for the 1965 film "Die! Die! My Darling!," which starred Tallulah Bankhead as a grieving, demented mother who terrorizes the young woman she blames for her son's death.

Mr. Matheson was also a busy television writer. He wrote for westerns like "Have Gun, Will Travel," "Cheyenne" and "Lawman," and for the war drama "Combat!" But he was mostly known for his work on science fiction and thriller series: "Alfred Hitchcock Presents," "Star Trek" and especially "The Twilight Zone," for which he wrote more than a dozen episodes, including the classic "Nightmare at 20,000 Feet," which starred William Shatner as an airplane passenger who spies a gremlin on the wing bent on crippling the plane.

Recalling the genesis of that episode, Mr. Matheson said: "I was on an airplane and I looked out and there were all these fluffy clouds and I thought, 'Gee, what if I saw a guy skiing across that like it was snow?,' because it looked like snow. But when I thought it over, that's not very scary, so I turned it into a gremlin out on the wing."

Mr. King wrote in a brief e-mail Tuesday that Mr. Matheson "was a seminal figure in the horror and fantasy genres, as important in his way as Poe or Lovecraft."

In his statement he wrote: "He fired my imagination by placing his horrors not in European castles and Lovecraftian universes, but in American scenes I knew and could relate to. 'I want to do that,' I thought. 'I must do that.' Matheson showed the way."

Richard Burton Matheson was born in Allendale, N.J., on Feb. 20, 1926, and grew up in Brooklyn. His parents were Norwegian immigrants; his father, Bertolf, installed tile flooring and helped operate speakeasies during Prohibition.

A voracious reader as a boy, Mr. Matheson graduated from Brooklyn Technical High School. He served in the Army in Europe during World War II, an experience that was the source of his novel "The Beardless Warriors." He studied journalism at the University of Missouri, after which he began writing fiction in earnest. For a time he worked at Douglas Aircraft. He published his first genre story, "Born of Man and Woman," about a young couple who give birth to a monster and keep him in the cellar, in 1950.

Mr. Matheson married Ruth Ann Woodson in 1952. She survives him. Besides his son R. C., he is also survived by another son, Christian; two daughters, Bettina Matheson Mayberry and Ali Marie Matheson; seven grandchildren; and two great-grandchildren.

Asked if his father, with whom he ran an entertainment company, had a motto or a saying that he lived by, R. C. Matheson said that he had kept a sign above his desk that read, "That which you think becomes your world."