Late one night last spring, William Bradshaw sat nervously in his study in Chesterfield waiting to make his media debut as a demonologist. A radio host in either Maine or Oregon — he can't remember which — was scheduled to call to discuss Bradshaw's new book, Sinister Among Us, a novel about hunting demons on a college campus.

It had been 47 years since Bradshaw first began his research of evil spirits that shatter human lives. Then, as now, an entire wall of his home office was lined with neatly arranged books on biblical scholarship. There, too, were two leather-bound copies of his Ph.D. thesis from Scotland's University of St. Andrews titled Demonology in the Old Testament and Hebrew Scriptures.

Bradshaw had prepared for that night's interview by sitting at his desk, making careful notes about the role of demons in the Bible and the more practical aspects of demonic possession and exorcism.

The phone rang. It was the radio host. "Dr. Bradshaw," he began, "do you believe that demonic possession causes heads to spin?"

The question caught Bradshaw off-guard. Stunned, he replied, "That's not relevant to the subject."

The radio host was equally surprised. Bradshaw, after all, was an expert on demons, and surely he must have seen the movie The Exorcist or read the book.

The interview went downhill from there.

"He wanted scary and spooky stuff, not scholarship," Bradshaw remembers now. "Most people don't understand demonology. They think demons are like ghosts and equate them with haunted houses. That's not what demonology is about." Ghosts, he continues, are the spirits of people who have died. Demons are evil spirits that have never been human.

Such is the life of America's best-known — and perhaps only — demonologist. "People look at me," Bradshaw concedes, "and say, 'What kind of kook are you?'" As a graduate student, he learned to deflect interest in his work by saying only that he studied the Old Testament.

Now 75, Bradshaw still resembles the dignified pastor and college president he was for four decades, staring out sternly at the world through steel-rimmed spectacles. He is a formal man who grew up in Lebanon, Missouri, and still speaks with an Ozark twang. Though retired, he dresses most days in a suit and tie. He eats his doughnuts with a fork.

He gets up early every morning, goes to his study and gets straight to work. He is currently working on two books, one on English grammar — he is most annoyed when people use "I" when they should use "me" — and the other a biography of an Ozark man who fought on the Union side during the Civil War. When he still played golf, he regularly shot in the 70s but preferred the driving range to the fairway.

Bradshaw is no charlatan. To him, demons are quite real. "I can't prove spirits exist," he says. "I can't prove God exists, that demons exist, that angels exist. They're invisible. You can't touch them, feel them, smell them. But sometimes something so absolutely marvelous and wonderful happens, beyond what you believe is man's ability to make things happen. Likewise, there are things so awful, so hideous, so dumb, that you just can't believe man is responsible for that activity. So you look for evidence of Satan."

Over the years, Bradshaw has met a number of people he believes were possessed. "The number of demon-possessed people compared to the number of people in the world is minuscule," he says. "But it's not uncommon. Right now, I would say I know fifteen to twenty."

All the events in the fictional Sinister Among Us are based on real life: the president of the college board of trustees who stole money from the scholarship fund. The prostitution ring operating out of a college dorm. The man whose skin broke out in blisters whenever touched by holy water. The woman whose life was a frightful misery until a clergyman determined she was possessed and exorcised the demon.

"Every incident has happened. I've been there," Bradshaw affirms. "But not in the same institution. My publisher was concerned about a lawsuit."

In the autumn of 1961 Bradshaw reported for the first time to the book-strewn office of Matthew Black, his Ph.D. thesis advisor at St Andrews.

To this day, his memory of that initial encounter is crystal clear. "Mr. Bradshaw," Bradshaw remembers Black telling him, "I want you to study demonology."

"At first I thought he was joking," Bradshaw adds. "But Dr. Black was not a humorous man."

Bradshaw was surprised — and disappointed. He had just moved his wife Betty June and their two young children to Scotland, for this? At the time, Black was one of the world's preeminent scholars of the Old Testament. Bradshaw had hoped to help him with his research on the Dead Sea Scrolls, which were first discovered in 1947. He wasn't interested in demons.

"I was not convinced it was a topic of great integrity," Bradshaw says, gazing up at the print of Winston Churchill that adorns his office wall. "It was scoffed at, especially on this side of the ocean."

Nothing in Bradshaw's background prepared him to study demons. His father, "a rough-and-tumble trial lawyer" in Lebanon, hoped his younger son would follow in his footsteps. He helped young William, known as Bud, overcome a childhood stutter by reciting poetry on Sunday afternoons.

Bradshaw attended the University of Missouri on a track scholarship and, like his father before him, served as student body president. The prospect of law school, though, made him nervous. Against his father's wishes, he decided to become a minister.

With Betty June's help, Bradshaw worked his way through Yale Divinity School. She typed and filed and he washed windows and sold shrubbery and storm windows door-to-door in New Haven. In 1958 he was ordained as a minister in the United Church of Christ and took up a pulpit in Pennsylvania. He left three years later to pursue his doctorate.

Dr. Black, Bradshaw realized, had his reasons for insisting that he study demonology. "It was only sixteen years after the Second World War," Bradshaw explains. "Many reputable scholars, especially theologians in England and Germany, had trouble believing that men were responsible for the atrocities of the war, especially the treatment of the Jews. Did evil spirits influence German thought? I was the first person to look at the topic. People didn't understand it. It set me apart. At the beginning, I was apologetic. I wanted to blame the whole thing on Dr. Black."

Bradshaw's research centered around one fundamental question: Where did demons come from? In the Old Testament, notes Bradshaw, God is all-powerful. By the New Testament, Satan has become God's equal and the two have begun the great cosmic battle that will end with Armageddon.

For three years, Bradshaw spent most of his time reading and re-reading the Bible and Hebrew scriptures. He left the library only to eat, sleep, meet with Black and play an occasional game of golf on St Andrews' famous course. And, for a few splendid weeks, to visit Jerusalem to examine the Dead Sea Scrolls in person.

"The scrolls were in a huge building," he happily recalls. "Well, it looked monstrous to me. It was full of long tables with the scrolls all spread out. It was like a jigsaw puzzle. You'd take a little piece and then try to figure out where it went."

Unfortunately, Bradshaw found little in the scrolls relating to demonic thought. "Dr. Black was disappointed," he says.

Bradshaw eventually discovered what he was looking for in the writings of Jewish scholars from the first and second centuries. One group of thinkers, the Apocalyptic school, believed — contrary to mainstream Jews — that God, Satan, demons and other supernatural forces intervened in human lives. Jesus was influenced by this group. Bradshaw wrote and defended his 400-page thesis and returned to America, assuming his demonology days were behind him.

"I'm not sure I'd gotten used to the idea of demons by the time I finished my Ph.D.," Bradshaw recalls. "I was married with two kids and a third on the way" — he and Betty June would eventually have four — "and I was mostly interested in getting done."

Bradshaw returned to the ministry, taking pulpits in St. Paul, Minnesota, and at the First Congregationalist Church of Los Angeles, which was in a building so large that the organ had two sets of pipes, one in front and one in back. When Bradshaw arrived in Los Angeles, the church was all-white. When he left three years later, it was fully integrated and offered Sunday school classes in seven languages.

He developed a talent for fundraising and had a reputation as a troubleshooter. The Board of Trustees at Lees College in Kentucky were impressed enough by his work in the church that they invited him to be the college president. Later, he became president of Patricia Stevens College in St. Louis.

"I had the background," Bradshaw says wryly. "I was a scholar of demonology."

"He's very modest," says his friend Dan Schlafly, a history professor at Saint Louis University. "He saved Patricia Stevens College from bankruptcy."

Bradshaw seldom discussed demonology during those years. "We were a long way removed from the Second World War," he says. "Life in the United States was good. Everything was nice and polite. Demons were haywire."

Still, he continued to read about demons. "Gradually over a period of time, there became no question in my mind that there was a cosmic battle going on. If you don't understand that, you can't understand demonology," he says.

Four years ago, with the encouragement of a few friends, including Schlafly, Bradshaw decided to write a book to teach laypeople demonology. It would, he decided, take the form of a novel.

"My dear, dear grandmother loved me," he says, "and was so interested in what I was learning, but she always seemed to go to sleep when I was talking to her. I decided to put what I knew into a format that wouldn't make people go to sleep. People remember stories."

Sinister Among Us follows Brad Green, president of fictitious Cyprus College, as he investigates an inexplicable series of crimes around campus that he comes to suspect may have been instigated by demons, or, rather, one demon-possessed individual.

Since its release last September, the book's sales have been modest, but it has earned praise as both a novel and as an introduction to demonology.

"The theology and history are correct," says Schlafly, who teaches a course on church history. "You can't say that about Dan Brown."

I've seen people of all walks of life who have been possessed by the devil," Bradshaw says, sitting up straight in his office chair. "There's no other reasonable explanation. Sometimes they do heinous things, like Hitler or Saddam Hussein. Sometimes they're just plain foolish.

"Who ruins their career over ten, fifteen thousand dollars? It's not chicken feed, but it won't make a dent in your legal fees. Politicians, especially. So many get caught doing things they shouldn't have. Eliot Spitzer. Lord, how can you figure a man that smart could be that dumb?"

The devil, Bradshaw goes on, likes to target people who have power and influence over others. He will also sometimes go after people who have great potential to do good to make sure it remains unfulfilled.

Of course, as Bradshaw points out, "It's hard to tell when someone is being very, very human and when someone is possessed. It's like a stomachache. Any number of things could be wrong. You have to consider the symptoms."

Is the skin on the patient's face unusually tight and smooth? Does he speak with a machine gun-like delivery and make hand gestures that have little to do with what he's saying? Does he have moments of unusual strength? Is he suddenly fluent in foreign languages he never studied? Does he speak in tongues? Can he foretell the future? Is he paranoid? Does he have horrible nightmares?

These are all signs, says Bradshaw, which may indicate a supernatural element at work.

Bradshaw will always shy away from making a diagnosis that a person is possessed — unless he brings it up first. "It's a belief so bizarre and unbelievable, especially in 21st-century America. If I were to suggest a person were possessed by a demon, it would cut off our rapport. A person has to want to be exorcised, like an alcoholic going to AA. It would have to be the right time and the right place."

Lately, Bradshaw has received a number of phone calls from people who wonder if various catastrophes in the world are the work of demons. "In good times, people don't pay much attention to evil spirits. When life is hard, interest spikes. But you can't always blame it on Satan."

Nonetheless, the rising interest in demons had led to some practical action on the part of the Roman Catholic Church. Pope John Paul II and his successor Benedict XVI both declared war on demons and decreed that each diocese would have at least one trained exorcist on staff.

The Archdiocese of St. Louis did not respond to phone inquiries about its own exorcists. Father Timothy Horner, a former headmaster at the Saint Louis Priory School, is not surprised. "In St. Louis, they have two exorcists," he says. "But they like to keep their identities quiet. Otherwise, they would be deluged with calls, people saying, 'My son is out of line, my daughter is out of line, my husband — they must be possessed!'"

A pastor observes certain rules of discretion. He does not betray confidences, even to his wife. In William Bradshaw's case, that reticence extends to his encounters with demons. He has participated in several exorcisms, but refuses to describe them in any detail.

"Some things are private matters," he says. "I don't capitalize on them." A few of the exorcised still live nearby and he doesn't want to expose them to public scrutiny.

"Each exorcism is different," he adds. "There are different people and different spirits with different personalities. Sometimes the demon leaves right away. But with an exorcism that takes two, three, four, five, six days, you see a progression and then you move back. Satan's not going to roll over and play dead. It's like a game of chess. A good exorcist will have someone with a different approach as backup." A typical exorcism team will include at least two exorcists, a psychologist and a medical doctor.

The first recorded exorcism, says Father Timothy Horner, takes place in Acts of the Apostles 19:14. It was an unmitigated disaster, with the demon attacking the exorcists and chasing them away.

"So many people think they can do an exorcism with no experience," Bradshaw says. "There's a lot of danger. An exorcist needs to be trained and qualified. The Roman Catholics are best at it. They have procedures for teaching how to do it." Catholics have a written liturgy for performing exorcisms and the Church keeps transcripts and videotapes of all exorcisms on file.

"The Church takes exorcism seriously," says Father Horner. "It treats it very carefully. Not anybody can get into it. The bishop chooses a person who is good and prayerful and has some knowledge of psychology. But goodness is the first thing required. The demon could jump out at you and say, 'You're no better than you should be.' If that happens, you should take to your heels as fast as you can."

A typical exorcism begins with a "deliverance," a series of prayers accompanied by soft music. "It gets the person in a certain spiritual mood," Bradshaw explains. "It also gets the exorcism team psyched up."

Then the battle begins. "A demon will very frequently use the voice of the person. You think it's the person talking. They use the body, the mind, the strength, the personality. It won't always have the same tone. Sometimes it's trying to soft-soap you and make a good impression. Or it'll try to scare the living daylights out of you."

The key element in any exorcism is that the possessed person has to want to be rid of the demon. "The average possessed person doesn't like himself and the things he does," Bradshaw says. "He's so relieved when it's over. But he's still spiritually weak. He needs to get counseling and help and be on guard against not allowing the demon back in his life."

Not all possessed people are correctly diagnosed and not all exorcisms are successful. "The great majority of demon-possessed people are never diagnosed," Bradshaw says. "They go see doctors about depression and outbursts and so forth, and they go from person to person to person. They get diagnosed with mental and emotional problems and have unhappy lives."

Still, Bradshaw will not hold demons responsible for all the world's evil. "Some scholars say that everything bad is caused by Satan, if you get hit by a car, if you slip and fall. I do not agree with this — it takes away all individual responsibility.

"Many people think they can play with the devil and get by. There's a certain enjoyment that comes from living on the edge and doing things you shouldn't and getting by. But who would go to a wedding and rape the bride? How can any human person be that cruel? Sometimes you have to believe there's an ultrahuman source at work."