Fear is personal. Whether it is heights or rats or failure, what frightens us is as varied as what makes us laugh or what we find beautiful. Taste matters. So do experience and culture. But just as some paintings are simply beautiful regardless of context, certain scares transcend the particular phobias of time and place. It’s the task of the horror movie director to create these enduring images, the ones that not only instantly frighten but endure, sticking in the subconscious and reappearing in dreams. No one has accomplished this as often or as long as Wes Craven. His influential movies such as A Nightmare on Elm Street,The Hills Have Eyes and Scream have helped define the billion-dollar modern horror industry. His nightmares have become ours. And they were formed in childhood at a place where most great directors of scary movies found inspiration: at home. His father died when he was three, and the ­memory that stuck was one of his father’s boiling temper: “It was the first thing that scared me,” Craven says.

His widowed mother, Caroline ­Craven, ran their house in Cleveland like a totalitarian state: Information flow was closely monitored and order maintained through strict rules enforced by the threat of punishment—the eternal kind. A Baptist pessimist with a ninth-grade education, she had a sad, rigid mouth hardened after a lifetime of tough luck. Her anxiety found its expression in her constantly twirling thumbs. She never remarried or even dated but instead poured all her energy, love and moral rectitude into her children, including the delicate youngest child, Wes. Battling sin was a full-time job—it required vigilance. Suspicion swirled around that house. No cursing! No sex! Forget the movies! Disney cartoons were all that was permitted. His mother refused to talk about race or politics or anything unpleasant. The taboo subjects, particularly sex, obsessed the teenage Craven, who sometimes felt he was going to hell.

He struggled to play the good son, attending Wheaton College, a strict Christian school, at his mother’s insistence. But in his first year there, at the age of 19, he suffered a viral infection in his spine that temporarily paralyzed him from the chest down. He was hospitalized for two months, and in that time, his life changed. He started writing poetry and short stories, some with dark themes. He adored Kafka’s paranoid literary vision. While recuperating he met a redheaded nursing student, Bonnie Broecker, who shared his fundamentalist upbringing, and after he dropped out of Wheaton, they began dating and then got married. He later finished college, and after graduating from Johns Hopkins’s master’s program in philosophy in 1964, Craven, then in his mid-20s, found work as an assistant professor of literature, first in Pennsylvania and then in Potsdam, New York. Continuing to write stories and a novel, he told Bonnie that by the age of 30 he wanted to be on the cover of Time magazine.

Impatient with his career advancement, he increasingly experienced strain in his family life. As their family grew with the birth of one child and then another, so did the culture war simmering inside the marriage. Bonnie was ready for a settled life, while Craven, who now rejected the ideas of his childhood, was searching for something to replace them with, leading to confusion and depressive spells. “I had so much rage as a result of years of being made to be a good boy,” he says. “I think when you’re raised to live within such rigid confines of thought and conduct, you think you are terrible if you violate the rules. It makes you crazy. Or it makes you angry. I’m surprised I never climbed a tower and shot people.”

He moved his family to Brooklyn, hoping to sell his novel, Noah’s Ark: The Journals of a Mad Man, about a sensitive, troubled son of the caretaker at a New York cemetery. No publishers were interested. Money became tight, and his marriage unraveled. Craven moved out, sleeping on couches on the Lower East Side. He’d given up the old religion, but hell still seemed close at hand. He had lost his family, and his dreams appeared out of reach. But by the next spring, his life would turn around. It began with a porn film.

Advertised in newspapers and sold as a mainstream film, Together, which smuggled full-frontal nudity and soft-core action under the guise of an educational documentary about sex, featured a tagline that played on anxieties about the generation gap: “Look for yourself! Judge for yourself! See what your children can show you about love!” It was just the kind of sly provocation that Sean ­Cunningham loved.

Wearing an easy smile that telegraphed a gregarious personality, Cunningham would become a pioneering horror director in the 1980s with Friday the 13th. But in the summer of 1969, when he met Craven, he had just made the transition from working off Broadway to producing drive-in movies. This first ­collaboration—Cunningham produced and directed; Craven helped with the editing—launched careers that would dominate the horror genre in the following decades.

Cunningham was charismatic, confident and always hustling. He talked a great game. All he wanted to do was scrape up enough cash to make his movies. He sold Together, which starred Marilyn Chambers, the adult-movie star who eventually gained notoriety in Behind the Green Door, to Hallmark Releasing Group, one of the many small exploitation companies then littering the film landscape, providing a steady stream of smut and brutality to grind-house theaters. The crucial insight of their marketers was that you could get away with anything if you did it in the name of art. They booked Together in shopping malls and suburban complexes. Free screenings were held for local police and civic groups. It opened in August 1971 and ran for 31 weeks at the Rialto Theater in New York. By February of the next year, Together had proved that porn could go mainstream, setting the stage for the blockbuster success of Deep Throat. ­Cunningham’s goal was to do the same thing with horror, which at the time was considered by many cultural critics to be barely more reputable than pornography.

Seeing some talent in the college professor who helped in the editing room, ­Cunningham asked Craven to direct the next project. Craven told him he had hardly seen a horror movie, let alone knew how to direct one. “You were raised fundamentalist,” Cunningham assured him. “Use it!”

What Craven came up with became one of the most influential horror movies of all time, The Last House on the Left. It opened when the film industry was changing. Rules about obscenity and violence were in flux. The “midnight movie” was reaching a young audience that embraced underground and cult films. The flesh-eating zombie and the remote serial killer emerged as the new dominant movie monsters, the vampire and werewolf of their day. In the Vietnam era, a new emphasis on realism took hold in the genre long dominated by escapist fantasy, and movies became more graphic.

This cultural shift took place in the same transitional period when some of the most ambitious Hollywood movies were being made. Many of the adventurous mainstream directors who belong to what is known as the New Hollywood got their start in horror. Francis Ford Coppola, Steven Spielberg and Peter Bogdanovich refined their craft on low-budget scares before moving on to what most people in the movie business consider their more mature work. At the same time, another class of directors more committed to the genre was getting started. George Romero, David Cronenberg, John Carpenter, Tobe Hooper and Wes Craven reinvented the conventions of the horror film outside of Hollywood, while William Friedkin, Brian De Palma and Roman Polanski smuggled more prestige horror productions into the studio system. Never in the history of the movies had so much talent been put to work frightening audiences.

Not only did the movies during this period address the same questions, but their answers had enough in common that a cohesive form of the genre developed by the end of the 1970s, when Ron ­Rosenbaum described this school of scary movies in Harper’s magazine. He called it the “New Horror.” Horror, he argued, “seems ready to supplant sex and violence in the hierarchy of mass sensation-seeking.” The popular narrative about the rise of the mainstream studio directors of the New Hollywood is that through the strength of their ideas they defied the bottom line to make something personal. The success of New Horror also depends on the personal visions of a few artists, but the best films were not merely victories by art in its endless battle against commerce. The most formative horror movies, such as The Last House on the Left, were made under tight constraints. Film shoots were quick and budgets shoestring. Auteur analysis tells only part of the story, since the films were also products of compromise and dispute, stitching together spare parts while tweaking old conventions.

Wes Craven felt the forbidden in society needed to be explored, the sins of the father exposed. Cunningham wanted to see lots of blood—up to a point. Their clashing personalities were part of what madeLast Housesuch a strange mongrel: a mix of canny marketing and confrontational art, exploitation and political statement.

The tension between the sadistic and the masochistic appeals of the movie was reflected in the divide between Cunningham and Craven. The producer saw Last House as an escape, an outlet for some dormant pain. But Craven, raised in an evangelical household, had a much deeper feel for the allure of self-sacrifice, of seeing abuse and brutality as transcendent. When people go to church, they are not merely escaping pain. They are brave enough to confront it, and that gives them a certain feeling of triumph. The trick was to find scares that could trigger a response from a secular audience looking for the experience of masochism, forcing them to confront the demons not only on-screen but also in themselves. The Last House on the Left challenged one of the most basic assumptions about the relationship between the audience and the filmmaker—namely, that people go to movies to enjoy themselves.

The story is a spin on Ingmar Bergman’s The Virgin Spring, hardly the usual source material for exploitation films. No director connoted European artistic seriousness as much as Bergman. Made only three years after his classic The Seventh Seal, The Virgin Spring is based on a medieval ballad about a virginal girl abducted in the woods on her way to church. She is raped and killed by three goatherds after her half sister invokes a pagan curse. Craven begins with the same story, but instead of going to church, the young girls head to a kind of secular church for young hipsters, a rock concert in the East Village. The band performing is called Bloodlust. Craven ups the ante on the violence by making the film less about assault than about a kind of beastly humiliation.

The killers don’t just rape the girl. They make her friend watch. Last House focuses on the faces of the victims with an unbearable realism. The killings in this film are not suspenseful or elegantly shot. They are amateurish, designed to maximize the most horrible primal fears. At one point, Krug, the gang leader, forces his victim to pee on herself. The next year a little girl does the same thing in The Exorcist, a movie that would reach (and upset) far more people. “I had sensed that it was one of the most humiliating things that happen to people,” Craven says. “There’s a really deep shame in peeing on yourself. To have someone make you do that, I knew it would be chilling, and when you do something like that, you are announcing, ‘This is not your parents’ Pontiac. This is about nastiness on a very deep level.’ ”

Cunningham says the in-your-face violence was a reaction to movies like Straw Dogs and Dirty Harry that use bloodshed to titillate. Precisely shot storms of bullets and blood are romantically choreographed to reveal a minimum of suffering. Not only are murders clean and quick, but they are accompanied by a variety of moral loopholes. Dustin Hoffman fights back against invaders, but he is standing up for his wife; Clint Eastwood’s vigilantism is at the expense of criminals.

Craven, by contrast, claims the graphic murders were a response to the media’s too delicate treatment of the Vietnam war. Because of the radicalism of the counterculture of the time, such themes were unavoidable. The Virgin Spring is a meditative movie, somber and discreet and littered with religious imagery. The father, yawning while his wife prays, seems barely interested in Christian religion. When he learns of the murder of his daughter, he questions his faith. He is redeemed in the final scene when he returns to the place of the original crime and promises to build a church. When a spring bubbles up over the dead girl, we witness Christian redemption.

There is no such miracle at the end of The Last House on the Left. In a godless world without redemption, it includes no struggle with faith. Instead, the senseless evil inspires just more senseless evil, adding up to a nihilism that invites no happy endings. The movie contrasts the savage, criminal gang with a bourgeois civilized family and reveals that they have more in common than you think. The marauding criminals begin as a kind of parody of a parent’s worst nightmare, but in these early scenes, Craven makes a point of showing us the dynamics within the gang to humanize them. He generates a sneaky sympathy for the killers.

The movie ends with more of a question mark than an exclamation point. We are left wondering what exactly the director was trying to say.Night of the Living Dead, the singularly influential zombie movie, which opened in 1968, is about a survivor battling hordes of zombies and ends on a note of existential defeat. What made Rosemary’s Baby, which opened the same year, such a radical break from the past was that unlike almost every other film about the battle with the devil, it has no fight to the finish at the end. Who knows what happens to the survivors of the zombie attack or to Rosemary after the movies end? What connects Last House *to the terror of *Night of the Living Dead and Rosemary’s Baby is moral ambiguity. That point is made emphatically in the final scene.

Once they discover the terrible crime, the Collingwoods, the victim’s parents, do not do the civilized thing and call the police to arrest the killers. Instead they take the law into their own hands, attacking and killing each member of the gang in increasingly brutal ways. A character is slashed to death by an electric boat fan. One of the most humiliating scenes in The Last House on the Left features the victim’s mother, played by Cynthia Carr, castrating one of the killers while giving him a blow job. (Carr had it written into her contract that she would not actually have to perform fellatio on-screen.)

The movie winds down to the climactic face-off between Krug and the victim’s father, the battle of the patriarchs. Craven imagined Krug would be killed with a scalpel, since the father was a doctor. Cunningham disagreed. With perfect exploitation instincts, he insisted on a chain saw; this was two years before The Texas Chainsaw Massacre. After killing Krug, the father slumps to the ground, stunned, shocked at the extent to which he has gone to avenge the death of his daughter. If the movie appears to invite the audience to revel in vigilante justice, this final shot, according to Craven, complicates it. The respectable parents have become what they most despise. The insanity of the criminal family is not so different from that found in the normal one. The original script of Last House starts with this quote from Yoko Ono: “Violence is just one of those feelings that come when you’re unable to communicate. Art is communication.”

Most audiences who first saw this movie thought they were going to see a trashy good time, a few dead bodies to laugh at. But they discovered a movie that was very difficult to enjoy without guilt. To Craven, the revenge at the end of Last House is designed to leave audiences disgusted, not exhilarated. It is the reverse of the morally cleansing conclusion of The Virgin Spring. The revenge is evidence that we all have a savage side and there is nothing to learn from it other than violence begets more violence. Not everyone bought this interpretation.

Most critics saw this violence as merely appealing to the basest dreams of teenage male thrill seekers. Part of the reason for this tension lies in how the movie was made. Cunningham thought it was too angry, disturbing and difficult to enjoy. Horror, to him, is “a roller-coaster ride.” When you design a roller coaster, you want something sturdy, tested and reliable. It has to scare people but not so much that they won’t feel safe. “In Craven’s mind, the parents had become that which they were trying to eradicate,” Cunningham says. “I’m not so sure. I think for most people it was just revenge.”

Cunningham was concerned about exhibitors rejecting the movie. When it started getting picked up by theaters, moving from city to city in short runs, he tried to cut out some of the more disturbing scenes to satisfy local theaters unhappy about the content of the movie. “Sean had very different opinions about the movie in general,” Craven says. “Once it was made, Sean thought it was disgusting and that we shouldn’t have done it.”

Craven stood by the film, defending it among friends. But he wasn’t always sure of himself. “It’s not an easy place to be—to write a horror film,” he says. “It’s hard. You go down the stairs to the dark to find these characters. It’s not a place that anyone can go, and sometimes it’s not a place that you want to go.” More than any other director of the era, Craven returned to this dark basement again and again, not just kicking off his career in horror but building one in it.

In later decades he made movies that challenged and expanded the genre, pushing it further into the mainstream with the help of a self-aware comic sensibility. In large part due to the imagination of Wes Craven, the horror film has become respectable.

But Craven has always maintained his sense of himself as an outsider, even when he no longer is one. He is quick to tell stories about being shouted at during cocktail parties for making detestable films and being derided by family members. And when I ask him about how he revolutionized the genre, he sighs, surrounded by posters of his movies in his spacious office in Studio City, Los Angeles. “All I am doing,” he says, “is ­rearranging the curtains in the insane asylum.”

From Shock Value: How a Few Eccentric Outsiders Gave Us Nightmares, Conquered Hollywood, and Invented Modern Horror, by Jason Zinoman, available from the Penguin Press in July.