The people behind The Conjuring  want you to know that it's based on a true story. Like, really want you to know. In the horror flick's latest trailer, there's commentary from the Perron family, the folks who, back in 1971, experienced all kinds of supernatural phenomena after moving into an isolated house in the woods of Harrisville, Rhode Island. Spliced in between movie footage are melodramatic proclamations from Perrons, warning how their story is finally being told because people "weren't ready for it" until now. Cue audience groans.

Fortunately, the Perron's account of dealing with demonic forces is directed by James Wan, the director behind 2011's excellent indie smash Insidious. Meaning, The Conjuring is a first-rate horror film, elegantly directed, full of dread, and featuring a superb cast playing developed characters. The film centers around Ed (Patrick Wilson) and Lorraine Warren (Vera Farmiga), the world renown demonologists who, in addition to the Perron case, famously investigated the Long Island house at the center of The Amityville Horror.

Before Ghost Hunters and all of its hokey counterparts, there were the Warrens, the highly respected married couple and forefathers of all current paranormal investigators. Ed, who passed away in 2006, was a demonologist ordained by the Catholic Church; Lorraine—with whom Wan and The Conjuring co-writers Chad and Corey Hayes directly consulted—was the resident clairvoyant. Together, they gave lectures at colleges, wrote several non-fiction books, and spent time in supposedly haunted and/or demon-plagued homes in order to cleanse the properties of all unwanted malevolent guests.

Instead of a biopic, The Conjuring focuses on one specific Warren case and, thanks to Wan's expertise, delivers some of Hollywood's best scares in years. Who knows—in time Wan's film could earn a spot alongside other genre staples of the realistic kind. Here, we trace the real-life inspirations behind classic horror movies to chart the tradition that The Conjuring is currently keeping alive.

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Written by Matt Barone (@MBarone)