Municipal and national governments refuse to acknowledge the loathsome straits into which the city has fallen.

This was Memphis in the late summer and fall of 1878, when yellow fever claimed more victims - 5,150 - than were killed in the Chicago fire, the San Francisco earthquake and the Johnstown flood together, as Molly Caldwell Crosby writes in the recently published "The American Plague: The Untold Story of Yellow Fever, the Epidemic That Shaped Our History" (A Berkley Book, $24.95).

Crosby, who lives in Memphis, vividly depicts the city at that time as a cesspool of pestilence, a circle of hell where the dead are better off than the living. The first-time author cleverly makes the dire circumstances even more horrendous by contrasting the epidemic with the preparations, only six months earlier, for the Memphis Mardi Gras Carnival, a symbol of the city's post-Civil War prosperity. The loss of population and business was so complete that in 1879 the city lost its charter and was operated as a state taxing district until 1891, when the name Memphis was restored.

"I find all these epidemics interesting," said Crosby. "So much nonfiction now focuses on natural disasters, and we can easily imagine what a hurricane can do or a 'perfect storm,' but it's more difficult for us to imagine what an epidemic was like."

Crosby grew up in Dallas, but was introduced to Memphis when she attended Rhodes College from 1991 to 1995. She married a Memphian, and while the couple lived in Washington, Crosby obtained a graduate degree in nonfiction writing at Johns Hopkins University and then worked in the editorial department of National Geographic, doing research and ghost-writing.

"I have an interest in medical history," Crosby said. "Some of the writers I worked with at National Geographic wrote about medical topics, and I got interested in that and learned to do the research. When we came back to Memphis, it fascinated me to discover that people still talked about the yellow fever epidemic and how it affected the city and its history."

Of course, at the time neither the victims of yellow fever nor the survivors realized the cause of the disease; as Linton Weeks wrote in "Memphis: A Folk History" (Parkhurst Publishers, 1982): "Memphis was destroyed by mosquitos in the 1870s."

Crosby said that publishers were skeptical about her proposal because the focus on Memphis seemed too regional, but a favorable, full-page review in the The New Times Book Review on Nov. 5 must have justified the efforts.

Besides, Memphis and its plight occupy only the first third of the book. The rest of "The American Plague" is devoted to medical hero Walter Reed, who, with his intrepid colleagues and volunteers in Cuba, discovered the cause of yellow fever - the Aedes aegypti mosquito - in a series of dangerous and, in some cases, fatal experiments. Three-hundred and sixty-five American soldiers had died in battle in the Spanish-American War, while 2,500 died of yellow fever, an imbalance that motivated the federal government to fund the search for the source of the disease.

Crosby traveled to Cuba to research Reed's efforts, but because Reed is such a well-known figure in the annals of medicine a great deal of widely available material exists about him and his career.

"Most of the Reed collection at the University of Virginia and his letters have been scanned in," said Crosby, "so I could do the research from here."

The 40 pages of notes that conclude the book (and make interesting reading on their own) testify to the broad and eclectic nature of Crosby's digging into original sources: newspapers, letters and diaries, military dispatches, old maps and photographs, books on a dazzling range of medical, historical and cultural subjects.

"I do enjoy research," said Crosby. "I definitely learned how important that is at National Geographic, which prides itself on thorough research. If you're going to cover a historical topic you have to research across the board to get the full picture."

That painstaking investigation is important not just for the sweep of detail but for getting things impeccably right. Whether Crosby is writing about Carnival preparations in Memphis, the death of a family in a plantation house in Mississippi or the itinerary and thoughts of Walter Reed in Havana, she provides meticulous documentation to back up the narrative. It's a process that has become increasingly important as nonfiction writers have recently juiced up their books by creating dialogue where none exists, by asserting or imagining that they were "on the scene" or just by making up details.

"That was a crucial issue for me," Crosby said. "I certainly feel that I'm a sort of purist. If you take a book like 'The Perfect Storm' (by Sebastian Junger), I think he really stretched the limits of what you should do in nonfiction. And I was determined, especially with my first book, that I wouldn't do that. I wanted every detail to have a basis in fact and record."

A comment about a first book brings up questions about the second book.

"I'm looking into a couple of different story ideas right now," said Crosby. "I'm moving away from medical history. I mean, once I got into the book the history part became more important than the medicine. So I'm moving in that direction."

"The American Plague" ends on a cautionary note.

Though yellow fever was largely eliminated throughout the world by vaccine in the 1940s, the disease is in resurgence because of the "evolutionary dexterity" of the mosquito and because of widespread poverty and unsanitary conditions in Africa and South American, "circumstances," Crosby writes, that "mirthose of Memphis in 1878."

"I tried not to be too sensationalist," she said, "and not use the phrase, 'Not if, but when,' but modes of transportation have changed so much, and the cycle of disease takes so little time now. The World Health Organization and the Center for Disease Control are definitely worried about it."

- Fredric Koeppel: 529-2376