"You can't believe the number of people with personal stories," author and Memphian Molly Caldwell Crosby said by phone a few weeks ago.

"I did an interview on The Diane Rehm Show on NPR, and they were getting calls from all over the world. One caller saying, 'My aunt had this disease.' And: 'My father survived this disease and then had mental problems.' Interesting that such a 'forgotten' disease had affected families just like mine."

The disease Crosby was referring to is encephalitis lethargica, the subject of her latest book, Asleep: The Forgotten Epidemic That Remains One of Medicine's Greatest Mysteries (Berkely Books). And indeed: The disease had affected her family — her own grandmother.

"She was 16 when she developed it," Crosby recalled. "And even though she went on to marry, she was always a little 'off,' a little distracted. I grew up hearing about it."

And maybe you've heard about it too. Post-encephalitic patients were the subjects of neurologist Oliver Sacks' well-known Awakenings, and "awakenings" is the right word to describe this brain disorder, which in response to the flu pandemic in the early 20th century claimed the lives of an estimated 5 million people worldwide.

For those who survived the weeks and sometimes months of what looked to loved ones and doctors like sleep, the years that followed could turn to hell: institutionalization and worse — as was the case of a 16-year-old girl named Rosie, who, after extracting her own teeth, was discovered by a hospital attendant holding her right eye in her hand. The next morning, Rosie calmly informed a nurse that her left eye had fallen out. The nurse found it entangled in the sheets of Rosie's bed. "I was like hypnotized at the time," Rosie admitted to her doctor. "Something made me do it."

Something also made encephalitis patients suffer a kaleidoscope of contradictory symptoms: hyperactivity; paralysis; incessant talking; tics; delirium; sleeping with eyes open; sleep leading to death; and death from sleep's opposite, insomnia.

Were, as some came to think, Adolf Hitler and Woodrow Wilson victims of encephalitis lethargica? Could it have inspired the imagination of Edgar Allan Poe ("The Fall of the House of Usher" and "The Premature Burial") or Washington Irving ("Rip Van Winkle") or the fairy tale "Sleeping Beauty"?

And what of the cause? A virus, a bacterium, an autoimmune response to the flu gone horribly haywire? Early observers (Crosby profiles a number of leading researchers over the decades, in Europe and in America) didn't know the cause. Doctors today aren't sure of the cause either. And scientists to this day can't say that another epidemic's impossible. Crosby simply said there's "concern."

She also added that her latest book is unlike her previous title — The American Plague, on the yellow fever epidemic — on at least one major level.

"The yellow fever story was filled with heroism and martyrdom, which would naturally appeal to any reader," Crosby said. "Asleep is more sad. It's not the triumph of medicine over disease. But it was more interesting to me in a lot of ways.

"I was starting from scratch, because there have not been books on the history of the disease. I went through medical records, but that meant jumping through hoops. When asylums were shut down in the 1970s, patient records were often destroyed. I had to get access to old files and old articles — in the 1920s and '30s, there were 9,000 articles."

Those articles also dealt with the subjects themselves — as in Rosie, above, and Crosby's half-dozen portraits of other encephalitis sufferers (including the wife of financier J.P. Morgan). But Crosby spotlights the doctors too, their personalities and personal setbacks, their professional achievements and the cost to their own lives.

Is Crosby now prepared to tackle a third medical story — one to go with The Plague (an "untold story" that shaped history) and Asleep (a "forgotten" history)?

"I'm thinking of a few topics," she said. "I'm talking to my agent. Maybe not a medical topic next time. But I said the same thing to my agent after the yellow fever book too."

Molly Caldwell Crosby will read from and sign copies of Asleep at Burke's Book Store on Thursday, April 1st, from 5:30 to

6:30 p.m.