David J. Skal, a witty historian of horror entertainment who found in movies like “Dracula” and “Rosemary’s Baby” both a mirror of evolving societal fears and a pressure-release valve for those anxieties, died on Jan. 1 in a car accident in Los Angeles. He was 71.

Mr. Skal was returning home after a movie and early dinner with his longtime partner, Robert Postawko, when an oncoming vehicle crossed a median and hit their car, said Malaga Baldi, Mr. Skal’s literary agent. Mr. Postawko was badly injured but survived the crash.

Mr. Skal was an author with encyclopedic knowledge of a subject not always taken seriously — movies meant to scare the bejesus out of people — whose erudition, combined with a chatty writing style, made his books lively and entertaining.

As an evangelist for horror, he was a regular guest on NPR, explicating frightful topics in a sonorous and friendly voice, and a consultant to Universal Studios for a theme park ride in Florida, “Halloween Horror Nights.” He also added commentary tracks to Universal’s DVD series of classic monster movies, from “Dracula” (1931) to “Creature From the Black Lagoon” (1954).

“One of the major functions that monsters provide for us is they let us process our fears about the real world without having to look at them too directly,” he told The New York Times in 2014.

He could riff in his writings on the cultural theories of Susan Sontag, Lionel Trilling and R.D. Laing. But his own critiques were never stuffy, grounded as they were in his personal fandom for a genre he first encountered as a boy living outside Cleveland. His first movie memory was watching “Frankenstein Meets the Wolf Man” on television.

“In the blue-collar suburb I grew up in, people who didn’t have much use for Don Giovanni responded to Dracula, and Frankenstein proved a serviceable substitute for Faust,” Mr. Skal wrote in the introduction to his book “Screams of Reason: Mad Science and Modern Culture” (1998), a study of mad scientists in movies and on television.

His most influential work, “The Monster Show: A Cultural History of Horror,” published in 1993, surveyed crazes for frightening films that reverberated with horrors in the real world, beginning with the silent classics “Nosferatu” (1922) and “The Hunchback of Notre Dame” (1923), which appeared after the mass deaths and bodily disfigurements of World War I.

Hollywood’s horror wave during the Great Depression — which besides “Dracula” included “Frankenstein” (1931) and “Dr. Jekyll and Mr. Hyde” (1932) — reflected, in Mr. Skal’s view, terrifying economic times. The Cold War, with its fears of foreign invaders, brought such escapist frights as “Invasion of the Body Snatchers” (1956), and the AIDS epidemic of the 1980s, when society was fixated on the dangers of blood contact, was paralleled by a boom in vampire movies.

Mr. Skal’s survey offered “persuasive evidence that in order to understand a culture, you must know what it fears,” Stefan Dziemianowicz, an authority on horror, fantasy and science fiction, wrote in a review in The Washington Post.

Dracula was a figure of particular fascination and scholarship for Mr. Skal. He wrote a book about the making of the 1931 movie starring Bela Lugosi, “Hollywood Gothic: The Tangled Web of Dracula From Novel to Stage to Screen” (1990); a biography of the movie’s director, “Dark Carnival: The Secret World of Tod Browning” (with Elias Savada, 1995); and “Something in the Blood: The Untold Story of Bram Stoker, the Man Who Wrote ‘Dracula’” (2016), about the author of the 1897 novel that revived vampire legends from around the world.

In addition, he was co-editor (with Nina Auerbach) of an annotated edition of Stoker’s novel, published in 1997.

In the bloodsucking Transylvanian count, whose bite penetrates both male and female victims to extract precious bodily fluids, Mr. Skal found a figure of high camp, but also a story with strongly carnal undertones. Reviewing “Something in the Blood” in The Times, Jason Zinoman wrote of Mr. Skal, “His command of the material combined with his gifts as a storyteller manage to make this an authoritative book without a dull moment, its wandering narrative always returning to the shadowy corners of Victorian sexuality.”

Mr. Skal, he added, “suggests that Stoker was a masochist with ‘a strongly transgender perspective’ muffled by the conventions of his age.”

In a 1995 interview with Terry Gross on the NPR program “Fresh Air,” Mr. Skal noted: “The sexual undercurrents of Dracula have been the subject of a lot of very interesting criticism, mostly in the last 20 years or so. And especially the homoerotic aspects.” He pointed out that Tod Browning ignored Universal Pictures’ effort to nix scenes of Dracula feasting on men, and that as a result the movie includes the metaphor of “a homoerotic seduction” of Renfield, the English solicitor Dracula invites up to his quarters.

Mr. Skal went on to delight Ms. Gross with his imitation of Renfield’s unearthly laugh. And Renfield was not the only character he could voice. “His impressions of Dracula kept adults and children in horrified giggles for hours,” Ms. Baldi, his agent, recalled.

David John Skal was born on June 21, 1952, in Garfield Heights, Ohio, to John Skal, a truck driver, and Lois (Fronek) Skal. In addition to Mr. Postawko, he is survived by a sister, Sandy Skal-Gerlock.

In 1974, Mr. Skal graduated with a B.A. from Ohio University in Athens, Ohio, where he was a film critic and an editor of the student newspaper. Before he turned to nonfiction, he wrote three science fiction novels set in dystopian futures: “Scavengers” (1980), “When We Were Good” (1981) and “Antibodies” (1988).

“As a precocious Midwestern grade schooler I was attracted to science fiction stories and films specifically because of their surreality, their nuttiness, their cracked-mirror reflections of a frightening Cold War decade when everything seemed on the verge of explosion and extinction,” he wrote in “Screams of Reason.” “I didn’t make a meaningful distinction between science fiction and horror; after all, weren’t they always shelved next to each other at the library and the bookstore?”

Reviewing “Screams of Reason” for The Times, the science writer Dick Teresi criticized it for finding far-fetched sexual references in films, as well as for what he called Mr. Skal’s limited understanding of real-world scientists. “His negative judgments about scientists are based on movies and visits to Disney World,” he wrote.

Mr. Skal had anticipated that reaction. In the book’s introduction he insisted, with his usual brio, that his subject was not the real world but pop culture’s distorted mirror of the world, reflecting our fears.

“My primary interest here,” he wrote, “is not the machinations of science itself but the fascinating life and times of its dark doppelgänger, the mad scientist, in all his overreaching glory.”