George is the tough guy.
Sandi is the terrified four-year-old.
Joanne is the outgoing adolescent.
Elizabeth knows them all.
Julia - who is all of them - knows none.

Julia Wilson* keeps a clock in every room of her house. When she looks at her watch, she checks not only the time but the date, to make sure that she has not somehow lost an entire chunk of her life.

Julia is, in novelist Kurt Vonnegut's phrase, "un-struck in time." "Since I was three or four," she says, "I've lost time. I remember being in the third grade, for instance, and I remember going back after Christmas break, and the next thing I knew it was fall, around October, and I was in the fifth grade."

Recounting the story now, two decades later, there is bewilderment and not-quite-subdued panic in her voice. "I knew who my teacher should have been, and I wasn't in her classroom," she says. "Everyone was working on a report, and I had no idea what I was supposed to be doing.

"I remember another time, eleven or twelve years ago," she recalls. "I was sitting in a kind of scummy bar, the kind of place I don't frequent. And I was talking to this guy, I had no idea who he was, but he seemed to know me a whole lot better than I knew him. It was, 'Whoa, get me out of here.' Believe me, this is not a relaxing way to live."

The fear of falling down one of those memory holes has become a preoccupation. "I might go home today and find out that my daughter, who is nine, graduated from high school last week," she says. "Can you imagine living your life that way?"

Julia is only now finding out how she loses time, and why. Her story is so strange that she herself is alternately fascinated and appalled by it. Julia has multiple personalities: She harbors within herself scores of alter egos. Some are aware of one another; some are not. Some are friendly; still others are murderously angry with Julia and leave signed notes threatening to cut and burn her.

For centuries, doctors have written up case histories that sound uncannily like Julia's. But it was only in 1980 that the bible of psychiatry, the Diagnostic and Statistical Manual of Mental Disorders, first recognized multiple personalities as a legitimate illness.

The condition is still far from the medical mainstream. Part of the problem is that it is too glitzy for its own good, too easy to write off as more suited to Hollywood and Geraldo Rivera than to serious clinicians and scientists: In a single human being, we are told, there might be both female and male personalities, right-handers and left-handers, personalities allergic to chocolate and others unaffected by it.

Just as the symptoms strain credulity, the cause, too, is almost beyond imagining. Nearly always, people who develop multiple personalities were subjected to horrifying abuse as children. Therapists recount one case after another of children tortured - for years - by parents, or siblings, or cults. The abuse is typically far worse than "ordinary" child abuse: These children were cut or burned or raped, repeatedly, and had no place they could see refuge.

Almost every therapist who has diagnosed a multiple personality was blinded at first by skepticism of ignorance. Robert Benjamin, a Philadelphia psychiatrist, recalls a woman he'd been treating ten months for depression. "Every now and again, she'd have slashed wrists. I'd ask how that happened, and she'd say, 'I don't know.'

"'What do you mean, you don't know?'
"'Well,' she'd say, 'I don't know. I certainly wouldn't do something like that. I'm a proper schoolteacher. And by the way, I find these strange clothes in my closet, outfits I wouldn't be cought dead in, and there are cigarette ashes in my car.'
"'What's so strange about that?'
"'I don't smoke,' she'd say, 'I'm on the Pennsylvania Turnpike halfway to Pittsburgh, and I don't know what I'm doing here.'

And then a couple of weeks later," Benjamin goes on, "a young woman walked into my office who looked like my patient, except she was dressed like a streetwalker, with a cigarette hanging out of her mouth. I knew my patient didn't smoke, and then I had my brilliant diagnostic moment. She looked at me and said, 'Well, dummy, have you figured out what's going on yet?"

He was so slow to catch on, Benjamin says, because he'd had drummed into him the old medical saying, "If you hear hoofbeats, think horses, not zebras. "But, precisely because the disorder is exotic, the diagnosis remains controversial. Even the harshest critics concede that some people have multiple personalities, but they insist that bedazzled therapists incorrectly slap the label on every confused patient who comes through the door.