Bob Moore's brain lay on a white plastic cutting board.

There was something beautiful about its convoluted hills and valleys, the way rivers of dusky purple and red meandered through the beige flesh.

And mysterious. Here was the essence of a man who had gone to Yale, loved a woman, fathered six children, relished ice cream and Mozart and Kierkegaard and e.e. cummings, favored questions over answers and change over complacency, hated camping, loathed golf, and, over the last 20 years, had slowly lost the capacity to understand any of it.

He had died that morning in a Wilmington nursing home, years past being able to feed himself or walk or recognize the woman he had married 56 years before.

What had gone wrong with his brain?

Before neuropathologist Mark Forman lifted his knife last December in a basement autopsy suite at the Hospital of the University of Pennsylvania, he could see that Bob Moore's brain wasn't normal. But it would be weeks before he could tell Moore's family what had made the man they loved disappear long before his heart stopped beating.

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Robert B. Moore, a Presbyterian minister, was a spiritual man, but he was also a believer in science and medicine.

After being diagnosed with Alzheimer's disease in 1993, at age 67, he entered a clinical trial of an experimental drug. He let doctors, intent on finding ways to detect dementia earlier, tap his spinal fluid and compare it with healthy people's.

And he decided that his brain would be autopsied at Penn's Center for Neurodegenerative Disease Research, founded and run by two nationally prominent dementia researchers.

Doctors can tell with about 90 percent accuracy whether a patient has Alzheimer's, the most common dementia. But looking through a microscope at brain tissue after death is still the only way to diagnose it with absolute certainty.

Perfecting diagnosis is critical in the emerging era of drugs designed for specific types of dementia.

But diagnosis is just the beginning. By studying brains from patients such as Bob Moore, scientists hope to figure out how and why the damage occurred - and learn to prevent it. More than one in five women and one in six men who reach age 65 will develop dementia before they die, a study this month reported. By 2050, more than 13 million Americans will have Alzheimer's, another study estimated.

"We want to cure this damn disease," said John Trojanowski, a neuropathologist who launched the center in 1982 with his wife, Virginia Lee, a biochemist and cell biologist. The center performed 86 autopsies last year - its record. Researchers there publish 40 to 50 scientific papers a year.

For Trojanowski, this is an epic battle.

"I talk about this as a threat to our economy and way of life that equals any natural disaster, and I think it will be worse... . The baby boomers start turning 60 this year," said Trojanowski, who is 59 himself. "We really are in a race with time."

For Moore's family, it's personal.

What exactly, they wonder, turned this gentle man into an unruly stranger who shouted obscenities and hit his wife? Why did the disease strike him a decade earlier than the average? Could the car accident that gave him amnesia briefly in 1950 have triggered this calamity years later?

Because of their family history, Moore's children also feel some urgency about the science that their father's brain cells may fuel. Three of their grandparents also died with dementia. Even their 78-year-old mother, who jokes that she is a "normal control" in Penn's studies, has a gene that raises risk for Alzheimer's.

With most now well into middle age, the children - a pediatric physical therapist, an architect, a computer consultant, a classical musician, a foreign-service officer, and a daughter whose own ministerial career was sidetracked by an autoimmune disease - all worry about their futures.

At 51, Alison Moore, the would-be minister, already has taken medicine for mild cognitive impairment, a condition that often precedes dementia.

Betsy Shieh, 45, the foreign-service officer, said her memory doesn't seem any worse than her peers' now. Still, she says, "when you forget something when your father's just died of Alzheimer's, you say: 'Oh s-, here I go.' "

Long after it was obvious that he was losing his fight with dementia, Bob Moore believed that doctors might save him. His children hope the cure he was so optimistic about will come in time for them.

A life driven by philosophy

Bob Moore came into the world with a superior brain. He used it hard and well.