Steve Luxenberg never met his Aunt Annie. As a matter of fact, he didn't know his mother had a sister until he was in his 40s -- more than 30 years after her death.

His book, Annie's Ghosts: A Journey into a Family Secret (Hyperion), which was published this month, documents his quest to re-create her life and to understand why his mother had concealed her existence.

Utilizing reporting skills that he had honed at The Baltimore Sun and then at The Washington Post as deputy editor and later head of the paper's investigative unit, Luxenberg, 56, discovers at least the outlines of the life of his aunt -- a retarded woman who had had a leg amputated and who had suffered from some form of mental illness. Annie was committed "temporarily" to an insane asylum, a detention that lasted 31 years.

During the course of his research, he uncovered many family secrets including that Annie had been committed when she was 21 years old, not 2, as his mother had claimed in 1995; that his mother had been named Bertha, not Beth, as she had been known; that his father, Jack, had had a psychiatric discharge from the Army, not one connected to a stomach ailment as the author had been told; and that his father was not a U.S. citizen.

His mother probably kept her sister secret because she was ashamed of her family's poverty, and the knowledge that the family had to put a mentally ill member in a state institution would only reinforce their poverty in the eyes of others.

She may have kept the secret from her fiance for fear that knowing about her sister might drive him away. "I try to make clear how important marriage was to my mother," the Baltimore resident says.

And in the 1930s, a stigma attached to the families of the mentally ill.

Even after Annie died in 1972, his mother continued the deception. Why? he asks in the book. "By 1972, I'm certain, the secret had become larger than Annie, had taken on a significance that went far beyond shame and stigma," he writes. "Having pretended all these years to be an only child, how could Mom now explain herself to her unknowing friends and family?"

His research leads him to believe that she may have kept the secret even from her husband.

After his death in 1980, why didn't she reveal the existence of her sister? "The longer she kept the secret, the larger it loomed, until it grew to such proportions in her mind that it overwhelmed and paralyzed her," explains Luxenberg, an associate editor at The Post.

Nonetheless, the author says he is not angry with his mother. "I think she suffered from her decisions," he says. "She wanted to disclose the truth, but felt she would be judged if she did. Nothing that she did hurt me, she hurt herself."

In the book, Luxenberg shows a thoroughness and dogged determination to learn what he could about his mother's state of mind.

For example, his mother had told him that she used to read Life, Look and the Saturday Evening Post when she was young. So, he perused issues of popular magazines in the late 1930s and early '40s for articles about mental illness, which his mother might have read.

"I came away with a strong feeling that Mom's worries about mental illness in her own family would have centered around two popular notions from that era: First, that psychiatry was a long way from curing the seriously sick; and second that genetics must be a factor," he writes.

"For a young woman with a sister thought to be schizophrenic, either notion must have been nothing short of terrifying."

Some readers may be disheartened by the difficulties he encountered in researching his family for his book, says Luxenberg, but he believes his story should encourage those wanting to find out about their own relatives.

"One of my goals was to show people who would be interested in doing research on their families that it was possible, that you don't have to be a genealogist" to succeed, he says.

"There is a how-to guide inherent in the narrative," the author insists. "I think people with enough drive and persistence can do what I did."

In addition, he hopes the book serves as a prod to get legislators to change privacy laws.

"There is now a conflict between privacy and history," the author notes. Some states have laws denying relatives and others the right to medical records of people who have died.

"It shouldn't be so hard for people to get information on their families," he continues. "We as a society need to agree that at some point, the medical records should be open to people with justified reason for access to the information."

Steve Luxenberg will discuss his book in a conversation with Scott Shane, reporter for The New York Times Washington bureau at Borders, 1801 K St., N.W., in the District on May 19 at 6:30 p.m. On May 26, at 7 p.m., at Sixth & Historic Synagogue in the District, he and Bob Woodward will discuss the implications of applying investigative journalism to family history in this latest installment of the Who Do You Think You Are? Genealogy Series. Tickets are $8 in advance, available at www.sixthandi.org; $10 at the door; or one free ticket with the purchase of the book upon entry.