Frauds use similar tricks, Nickell says, whether they’re faking U.F.O.s or Jesus Christ. Illustration by Cristoph Niemann

The village of Lily Dale, New York, has been home to strange doings for so long that it hardly calls attention to itself anymore. Its brightly painted Victorian homes, clustered by the cobalt waters of Cassadaga Lake, an hour southwest of Buffalo, could belong to almost any artists’ colony or vacation retreat. On summer days, the volunteer fire department throws barbecues and pancake breakfasts, and the citizens sun themselves on their front porches, calling out to one another across the narrow, sloping streets. Were it not for the wooden signs that hang from nearly every house—“Virgil Patterson, Medium,” “Ghost Crossing,” “Readings Available”—you might never guess that this is the world’s largest center for the religion of Spiritualism. Yet, for ten weeks every summer, nearly twenty-five thousand visitors come here to talk to their dead. Lily Dale, they believe, is a kind of satellite dish for the spirit world.

On a recent afternoon, a hundred and fifty people were gathered in a forest clearing near the town’s pet cemetery, facing the remains of an ancient oak known as Inspiration Stump. For the past hour, a succession of mediums had come before the crowd, conveyed a few messages from the dearly departed, and disappeared into the trees again. Now a woman with red hair and a flowing white blouse glided onstage, her eyes bulging with precognition. “You, in the violet shirt,” she shouted, lifting a bony finger toward an elderly woman with thick glasses and white curls. “I see a man with silver hair. He’s worried about something in your basement, something structural. He’s saying you can’t put off fixing it anymore.” The old woman blinked and braced for more, but the medium had already moved on to the next spirit in line. The afterlife, it seemed, was thronging with communicants.

Looking around at the crowd, I didn’t see a single sideward glance or quizzical smile, and the strength of all that belief was a little unsettling. Already that morning, a man with snow-white hair and a blissful mien had ministered to me at a “healing service” in the Spiritualist church, mumbling incantations as he laid his hands on my forehead. Later, during a private reading by the Reverend John White, a vice-president of the Spiritual Science Fellowship, I was told that I was an Anglo-Saxon crusader in a previous life, that I had a Native American spirit guide, that I would one day go bungee-jumping on a “spiritual warrior quest” to cure my fear of heights, and that my body needed more antioxidants. I couldn’t really see myself in what he said (though I am afraid of heights), or bring myself to believe, as one medium put it, that educated people give off a pink aura, while extroverts glow yellow. But the people at Lily Dale listened with rapt expressions. When the spirits advised one man to go back to school, another to lay off sweet pickles, they nodded their heads and waited for the next revelation.

All except one. As the crowd got up to leave, I caught sight of a curious figure standing at the back. He was tall and bulky, with dark shades and a battered straw hat. When I walked down the aisle past his row, he fell in step beside me, his lips pursed beneath a trim gray mustache. “I changed my look in the car before I came over,” he murmured, as the crowd dispersed. “You wouldn’t want them to recognize me.”

His name was Joe Nickell, and this was one of his simpler disguises. He has been known to shave his mustache, walk with a cane, or do any number of things to fool his suspects, who know his usual persona all too well. At the age of fifty-eight, Nickell is the country’s most accomplished investigator of the paranormal. He has appeared on “Oprah,” “20/20,” “Larry King Live,” and dozens of other television shows—a sharp-tongued and amiably pompous old gumshoe, with thinning gray hair and shopworn tweeds. He has written or co-written sixteen books, all of which are still in print. The latest is called “Real-Life X-Files.”

Like a lot of people, I first heard of Nickell through one of his alter egos. I’d been told that he is an expert on antique ink and paper, and the forensic analysis of historic documents. His Ph.D. dissertation was on literary investigation, and in 1990 he published one of the few sourcebooks in the field, “Pen, Ink & Evidence.” Nickell has since been asked to authenticate everything from manuscripts of the Gettysburg Address to “The Bondwoman’s Narrative,” which is believed to be the first novel written by a black woman in America. When I met him, he was embroiled in a debate on the authorship of the poem “An Account of a Visit from Saint Nicholas,” which is better known as “The Night Before Christmas” and is perhaps the country’s most famous poem.

But all that, I found, was just moonlighting. Nickell’s day job is with the Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP, for short). Lily Dale wasn’t among his current targets, but it was a good example of the kinds of communities he tends to infiltrate. We had arranged this rendezvous earlier that day. Now, as we walked back into town, Nickell said nothing for a while. He has an odd fondness for Lily Dale. Its mediums are believers rather than showmen or frauds. They have to be active members of the Spiritualist church in order to own a house in town, and their psychic abilities must be tested and approved by the Lily Dale Board of Directors. Any medium who has had three or more complaints lodged against him in a year has to be retested.

Still, few mediums can stand up to careful scrutiny. Two years ago, “Dateline NBC” asked Nickell to serve as a consultant for a segment on the medium John Edward, the host of the show “Crossing Over.” At Nickell’s urging, the producers kept Edward and his audience apart before the show, so that he couldn’t glean any information for his psychic readings. During the taping, though, Edward surprised everyone. He communicated with a spirit named Anthony, who appeared to be the dead father of one of the show’s cameramen. When Edward mentioned a ring, the cameraman recalled that he had slipped one on his father’s finger at the funeral. “That did seem kind of amazing,” Nickell told me. Only later did Edward admit that he had talked to the cameraman about his father once before, while they were shooting a roll of background footage for the show.

“We caught him cheating,” Nickell said, but his voice held an odd disappointment. Someday, he insists, his investigations may unveil a wonder that even science can’t explain away. Yet his subjects inevitably fail him. A hundred and twenty-three years ago, when Lily Dale was founded, the dead at least had style. Western New York was known as the “burned-over district” then—a crucible for Mormonism, Christian Science, Seventh-Day Adventism, and countless cults and utopian colonies. To attract audiences, Spiritualists levitated objects during séances, conjured “spirit paintings” of the dead out of thin air, and covered entire slates in ghostly Victorian prose. “Oh, my darling, thank God, thank God, at last I’m through,” Harry Houdini’s dead mother told him when she contacted him through a medium in 1922. Never mind that she had spoken only German and broken English when she was alive.