Otherwise perfectly normal people talk haltingly of visits by aliensýthin, gray, spectral beings with huge, black, hollow eyes. Appearing most often during the night, in bedrooms or on lonely stretches of highway, these ephemeral apparitions harvest ova, steal time and implant transistorized tracking devices in those they encounter.

A highly respected teacher and scholar who has written two well-regarded books on the German philosopher Martin Heidegger, Michael Zimmerman first became intrigued with the alien abduction phenomenon in 1988.

At a bookshop in New Yorkýs JFK airport, on his way to present a philosophy paper in Turkey, Zimmerman picked up Communion, Whitley Strieberýs supposedly firsthand account of alien contact.

"I was totally amazed and shocked," Zimmerman says. But the affable and articulate professor didnýt take aliens too seriously, having little time to ponder the meaning of these bizarre events. He put the phenomenon into a compartment of his mind that said "weird, but who knows what to make of it?"

Four years later, Zimmerman read another book about alien abduction, Secret Life, by Temple University historian David Jacobs. This book claims that aliens are flesh-and-blood beings from outer space. What gave Zimmerman a "sinking feeling that there is something to all of this" is that the book was introduced by John Mack, a Pulitzer Prizeýwinning Harvard psychiatrist. Mackýs research into alien abduction, which he does not take literally in the way that Jacobs does, convinced Zimmerman that "experiencers are not crazy."

"Experiencers," rather than abductees, is what Mack prefers calling people who contend that they have encountered aliens. In his 1994 book, Abduction: Human Encounters with Aliens, Mack recounts the stories of a dozen experiencers. He has now interviewed more than 120 people who say theyýve encountered aliens. And he has matched from 40 to 50 experiencers in terms of age, race, gender and economic status with a control group of the same number who have never met an alien, finding little difference in the psychological profiles of the two groups.

This work so astounded Zimmerman that he has signed on as a program adviser to Mackýs Program for Extraordinary Experience Research at Harvard.

"Iým trying to help make sense of the phenomenon, trying to give some constructive interpretation," says Zimmerman. "I see my role as trying to make the study of this phenomenon academically respectable."

LACK OF RESPECT is what any academician or scientist might be worried about when delving into a subject as controversial and scientifically taboo as UFOs and aliens. Yet, going where angels fear to tread doesnýt intimidate Zimmerman.

As he talks, sitting in his Newcomb Hall office surrounded by sagging bookshelves filled with probably 10,000 booksýall of them probably read, tooýZimmerman sips

ginseng tea, comfortable in his role as philosopher, seeker of truth.

The motivating factor, the pull into the vortex leading Zimmerman toward trying to figure out the alien abduction phenomenon, seems to be his compassion for the experiencersý suffering. And his compassion for their suffering may be linked to his understanding of Buddhist philosophy, partly achieved through long hours of sitting in meditation with his knees screaming. At its simplest, Buddhism says that life is characterized by suffering. And suffering is caused by desire, delusion and anger. But there is a cure for suffering. It is knowledge, compassion and letting things be.

What Mack has found in his researchýand what touches and distresses Zimmermanýis that the experiencers are truly suffering. They are terrified. They usually want the alien visitations to stop. Experiencers often canýt talk about the incidents with family members, and they are afraid of losing their jobs if they discuss their experiences with co-workers.

"Their suffering occurs in part because they canýt talk about this," Zimmerman says.

Our civilization doesnýt leave much room for comprehending off-the-wall, out-of-this-world occurrences.

"In our society, we have only two options to explain what these people are experiencing," Zimmerman says. "One is that itýs some kind of hallucinatory event, strictly a mental, private phenomenon that is a pathology, which is fixable, but doesnýt mean anything. Itýs all delusion."

The other possibility is that there are "real" aliens coming in on spacecraft and abducting people, intervening in their lives, doing genetic engineering, taking over the planet and turning humans into hybrids.

"That is hard to believe," says Zimmerman. "That is a real stretch for me to accept."

Yet, from Mackýs research, Zimmerman has concluded that the first option is implausible, too. "There are too many similarities in accounts," Zimmerman says. "Thereýs just too much richness and robustness of detail.

"Mack says the effect, the emotions associated with people telling their stories to him, are so powerfulýthe terror is so real to themýthey canýt be making it up."

SO, WHERE DOES this outlandish phenomenon leave a serious, open-minded scholar? If two hypotheses donýt hold up, another conjecture must be tried.

"If we donýt accept the literal hypothesis and we donýt accept the private hallucination interpretation, then whatýs another option?" Zimmerman asks.

The third option would be that "these people are encountering a different dimension of reality."

Different dimension of reality? This is really out there.

But Zimmerman says a different

dimension of reality might be not so much "out there" as right here, "in the soul realm."

"One way to interpret it would be that these people are encountering entities from the soul realm," Zimmerman says.

In all societiesýin virtually all of human historyýpeople have believed in three different realms. First is the physical, material realm, which includes our bodies and everything that can be discerned with our normal sensesýall that can be tasted, felt, seen and measured. "This is the realm we normally inhabit," says Zimmerman.

Then thereýs the realm of the spirit, the God realm. "The spirit realm is beyond form," says Zimmerman.

The third realm that Zimmerman says many Americans have forgotten about is the soul realm. The soul realm is an intermediary dimension, between the spirit and material realms. Itýs inhabited by all kinds of denizens: demigods, angels, devils, elves, gnomes and fairiesý"all these weird beings that people have always reported seeing," says Zimmerman.